|
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Diagnostics;
using System.Windows.Threading;
using System.Windows.Controls.Primitives;
using System.Windows.Data;
using System.Windows;
using System.Windows.Media;
using System.Windows.Markup;
using System.Windows.Input;
using System.Windows.Automation.Peers;
using MS.Utility;
using MS.Internal;
using MS.Internal.Controls;
using MS.Internal.Data;
using MS.Internal.Hashing.PresentationFramework; // HashHelper
using MS.Internal.KnownBoxes;
using MS.Internal.PresentationFramework;
using MS.Internal.Utility;
namespace System.Windows.Controls
{
/// <summary>
/// The base class for all controls that have multiple children.
/// </summary>
/// <remarks>
/// ItemsControl adds Items, ItemTemplate, and Part features to a Control.
/// </remarks>
// Needs DefaultEvent("ItemsChanged") ?
[DefaultEvent("OnItemsChanged"), DefaultProperty("Items")]
[ContentProperty("Items")]
[StyleTypedProperty(Property = "ItemContainerStyle", StyleTargetType = typeof(FrameworkElement))]
[Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // cannot be read & localized as string
public class ItemsControl : Control, IAddChild, IGeneratorHost, IContainItemStorage
{
#region Constructors
/// <summary>
/// Default ItemsControl constructor
/// </summary>
/// <remarks>
/// Automatic determination of current Dispatcher. Use alternative constructor
/// that accepts a Dispatcher for best performance.
/// </remarks>
public ItemsControl() : base()
{
ShouldCoerceCacheSizeField.SetValue(this, true);
this.CoerceValue(VirtualizingPanel.CacheLengthUnitProperty);
}
static ItemsControl()
{
// Define default style in code instead of in theme files.
DefaultStyleKeyProperty.OverrideMetadata(typeof(ItemsControl), new FrameworkPropertyMetadata(typeof(ItemsControl)));
_dType = DependencyObjectType.FromSystemTypeInternal(typeof(ItemsControl));
EventManager.RegisterClassHandler(typeof(ItemsControl), Keyboard.GotKeyboardFocusEvent, new KeyboardFocusChangedEventHandler(OnGotFocus));
VirtualizingStackPanel.ScrollUnitProperty.OverrideMetadata(typeof(ItemsControl), new FrameworkPropertyMetadata(new PropertyChangedCallback(OnScrollingModeChanged), new CoerceValueCallback(CoerceScrollingMode)));
VirtualizingPanel.CacheLengthProperty.OverrideMetadata(typeof(ItemsControl), new FrameworkPropertyMetadata(new PropertyChangedCallback(OnCacheSizeChanged)));
VirtualizingPanel.CacheLengthUnitProperty.OverrideMetadata(typeof(ItemsControl), new FrameworkPropertyMetadata(new PropertyChangedCallback(OnCacheSizeChanged), new CoerceValueCallback(CoerceVirtualizationCacheLengthUnit)));
}
private static void OnScrollingModeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ShouldCoerceScrollUnitField.SetValue(d, true);
d.CoerceValue(VirtualizingStackPanel.ScrollUnitProperty);
}
private static object CoerceScrollingMode(DependencyObject d, object baseValue)
{
if (ShouldCoerceScrollUnitField.GetValue(d))
{
ShouldCoerceScrollUnitField.SetValue(d, false);
BaseValueSource baseValueSource = DependencyPropertyHelper.GetValueSource(d, VirtualizingStackPanel.ScrollUnitProperty).BaseValueSource;
if (((ItemsControl)d).IsGrouping && baseValueSource == BaseValueSource.Default)
{
return ScrollUnit.Pixel;
}
}
return baseValue;
}
private static void OnCacheSizeChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ShouldCoerceCacheSizeField.SetValue(d, true);
d.CoerceValue(e.Property);
}
//default VCLU will be Item for the flat non-grouping case
private static object CoerceVirtualizationCacheLengthUnit(DependencyObject d, object baseValue)
{
if (ShouldCoerceCacheSizeField.GetValue(d))
{
ShouldCoerceCacheSizeField.SetValue(d, false);
BaseValueSource baseValueSource = DependencyPropertyHelper.GetValueSource(d, VirtualizingStackPanel.CacheLengthUnitProperty).BaseValueSource;
if ( !((ItemsControl)d).IsGrouping && !(d is TreeView) && baseValueSource == BaseValueSource.Default )
{
return VirtualizationCacheLengthUnit.Item;
}
}
return baseValue;
}
private void CreateItemCollectionAndGenerator()
{
_items = new ItemCollection(this);
// ItemInfos must get adjusted before the generator's change handler is called,
// so that any new ItemInfos arising from the generator don't get adjusted by mistake
// (see Win8 690623).
((INotifyCollectionChanged)_items).CollectionChanged += new NotifyCollectionChangedEventHandler(OnItemCollectionChanged1);
// the generator must attach its collection change handler before
// the control itself, so that the generator is up-to-date by the
// time the control tries to use it (bug 892806 et al.)
_itemContainerGenerator = new ItemContainerGenerator(this);
_itemContainerGenerator.ChangeAlternationCount();
((INotifyCollectionChanged)_items).CollectionChanged += new NotifyCollectionChangedEventHandler(OnItemCollectionChanged2);
if (IsInitPending)
{
_items.BeginInit();
}
else if (IsInitialized)
{
_items.BeginInit();
_items.EndInit();
}
((INotifyCollectionChanged)_groupStyle).CollectionChanged += new NotifyCollectionChangedEventHandler(OnGroupStyleChanged);
}
#endregion
#region Properties
/// <summary>
/// Items is the collection of data that is used to generate the content
/// of this control.
/// </summary>
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
[Bindable(true), CustomCategory("Content")]
public ItemCollection Items
{
get
{
if (_items == null)
{
CreateItemCollectionAndGenerator();
}
return _items;
}
}
/// <summary>
/// This method is used by TypeDescriptor to determine if this property should
/// be serialized.
/// </summary>
[EditorBrowsable(EditorBrowsableState.Never)]
public bool ShouldSerializeItems()
{
return HasItems;
}
/// <summary>
/// The DependencyProperty for the ItemsSource property.
/// Flags: None
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemsSourceProperty
= DependencyProperty.Register("ItemsSource", typeof(IEnumerable), typeof(ItemsControl),
new FrameworkPropertyMetadata((IEnumerable)null,
new PropertyChangedCallback(OnItemsSourceChanged)));
private static void OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ItemsControl ic = (ItemsControl) d;
IEnumerable oldValue = (IEnumerable)e.OldValue;
IEnumerable newValue = (IEnumerable)e.NewValue;
((IContainItemStorage)ic).Clear();
BindingExpressionBase beb = BindingOperations.GetBindingExpressionBase(d, ItemsSourceProperty);
if (beb != null)
{
// ItemsSource is data-bound. Always go to ItemsSource mode.
// Also, extract the source item, to supply as context to the
// CollectionRegistering event
ic.Items.SetItemsSource(newValue, (object x)=>beb.GetSourceItem(x) );
}
else if (e.NewValue != null)
{
// ItemsSource is non-null, but not data-bound. Go to ItemsSource mode
ic.Items.SetItemsSource(newValue);
}
else
{
// ItemsSource is explicitly null. Return to normal mode.
ic.Items.ClearItemsSource();
}
ic.OnItemsSourceChanged(oldValue, newValue);
}
/// <summary>
/// Called when the value of ItemsSource changes.
/// </summary>
protected virtual void OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue)
{
}
/// <summary>
/// ItemsSource specifies a collection used to generate the content of
/// this control. This provides a simple way to use exactly one collection
/// as the source of content for this control.
/// </summary>
/// <remarks>
/// Any existing contents of the Items collection is replaced when this
/// property is set. The Items collection will be made ReadOnly and FixedSize.
/// When ItemsSource is in use, setting this property to null will remove
/// the collection and restore use to Items (which will be an empty ItemCollection).
/// When ItemsSource is not in use, the value of this property is null, and
/// setting it to null has no effect.
/// </remarks>
[Bindable(true), CustomCategory("Content")]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public IEnumerable ItemsSource
{
get { return Items.ItemsSource; }
set
{
if (value == null)
{
ClearValue(ItemsSourceProperty);
}
else
{
SetValue(ItemsSourceProperty, value);
}
}
}
/// <summary>
/// The ItemContainerGenerator associated with this control
/// </summary>
[Bindable(false), Browsable(false), EditorBrowsable(EditorBrowsableState.Advanced)]
public ItemContainerGenerator ItemContainerGenerator
{
get
{
if (_itemContainerGenerator == null)
{
CreateItemCollectionAndGenerator();
}
return _itemContainerGenerator;
}
}
/// <summary>
/// Returns enumerator to logical children
/// </summary>
protected internal override IEnumerator LogicalChildren
{
get
{
if (!HasItems)
{
return EmptyEnumerator.Instance;
}
// Items in direct-mode of ItemCollection are the only model children.
// note: the enumerator walks the ItemCollection.InnerList as-is,
// no flattening of any content on model children level!
return this.Items.LogicalChildren;
}
}
// this is called before the generator's change handler
private void OnItemCollectionChanged1(object sender, NotifyCollectionChangedEventArgs e)
{
AdjustItemInfoOverride(e);
}
// this is called after the generator's change handler
private void OnItemCollectionChanged2(object sender, NotifyCollectionChangedEventArgs e)
{
SetValue(HasItemsPropertyKey, (_items != null) && !_items.IsEmpty);
// If the focused item is removed, drop our reference to it.
if (_focusedInfo != null && _focusedInfo.Index < 0)
{
_focusedInfo = null;
}
// on Reset, discard item storage
if (e.Action == NotifyCollectionChangedAction.Reset)
{
((IContainItemStorage)this).Clear();
}
OnItemsChanged(e);
}
/// <summary>
/// This method is invoked when the Items property changes.
/// </summary>
protected virtual void OnItemsChanged(NotifyCollectionChangedEventArgs e)
{
}
/// <summary>
/// Adjust ItemInfos when the Items property changes.
/// </summary>
internal virtual void AdjustItemInfoOverride(NotifyCollectionChangedEventArgs e)
{
AdjustItemInfo(e, _focusedInfo);
}
/// <summary>
/// The key needed set a read-only property.
/// </summary>
internal static readonly DependencyPropertyKey HasItemsPropertyKey =
DependencyProperty.RegisterReadOnly(
"HasItems",
typeof(bool),
typeof(ItemsControl),
new FrameworkPropertyMetadata(BooleanBoxes.FalseBox, OnVisualStatePropertyChanged));
/// <summary>
/// The DependencyProperty for the HasItems property.
/// Flags: None
/// Other: Read-Only
/// Default Value: false
/// </summary>
public static readonly DependencyProperty HasItemsProperty =
HasItemsPropertyKey.DependencyProperty;
/// <summary>
/// True if Items.Count > 0, false otherwise.
/// </summary>
[Bindable(false), Browsable(false)]
public bool HasItems
{
get { return (bool) GetValue(HasItemsProperty); }
}
/// <summary>
/// The DependencyProperty for the DisplayMemberPath property.
/// Flags: none
/// Default Value: string.Empty
/// </summary>
public static readonly DependencyProperty DisplayMemberPathProperty =
DependencyProperty.Register(
"DisplayMemberPath",
typeof(string),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
string.Empty,
new PropertyChangedCallback(OnDisplayMemberPathChanged)));
/// <summary>
/// DisplayMemberPath is a simple way to define a default template
/// that describes how to convert Items into UI elements by using
/// the specified path.
/// </summary>
[Bindable(true), CustomCategory("Content")]
public string DisplayMemberPath
{
get { return (string) GetValue(DisplayMemberPathProperty); }
set { SetValue(DisplayMemberPathProperty, value); }
}
/// <summary>
/// Called when DisplayMemberPathProperty is invalidated on "d."
/// </summary>
private static void OnDisplayMemberPathChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ItemsControl ctrl = (ItemsControl) d;
ctrl.OnDisplayMemberPathChanged((string)e.OldValue, (string)e.NewValue);
ctrl.UpdateDisplayMemberTemplateSelector();
}
// DisplayMemberPath and ItemStringFormat use the ItemTemplateSelector property
// to achieve the desired result. When either of these properties change,
// update the ItemTemplateSelector property here.
private void UpdateDisplayMemberTemplateSelector()
{
string displayMemberPath = DisplayMemberPath;
string itemStringFormat = ItemStringFormat;
if (!String.IsNullOrEmpty(displayMemberPath) || !String.IsNullOrEmpty(itemStringFormat))
{
// One or both of DisplayMemberPath and ItemStringFormat are desired.
// Set ItemTemplateSelector to an appropriate object, provided that
// this doesn't conflict with the user's own setting.
DataTemplateSelector itemTemplateSelector = ItemTemplateSelector;
if (itemTemplateSelector != null && !(itemTemplateSelector is DisplayMemberTemplateSelector))
{
// if ITS was actually set to something besides a DisplayMember selector,
// it's an error to overwrite it with a DisplayMember selector
// unless ITS came from a style and DMP is local
if (ReadLocalValue(ItemTemplateSelectorProperty) != DependencyProperty.UnsetValue ||
ReadLocalValue(DisplayMemberPathProperty) == DependencyProperty.UnsetValue)
{
throw new InvalidOperationException(SR.DisplayMemberPathAndItemTemplateSelectorDefined);
}
}
// now set the ItemTemplateSelector to use the new DisplayMemberPath and ItemStringFormat
ItemTemplateSelector = new DisplayMemberTemplateSelector(DisplayMemberPath, ItemStringFormat);
}
else
{
// Neither property is desired. Clear the ItemTemplateSelector if
// we had set it earlier.
if (ItemTemplateSelector is DisplayMemberTemplateSelector)
{
ClearValue(ItemTemplateSelectorProperty);
}
}
}
/// <summary>
/// This method is invoked when the DisplayMemberPath property changes.
/// </summary>
/// <param name="oldDisplayMemberPath">The old value of the DisplayMemberPath property.</param>
/// <param name="newDisplayMemberPath">The new value of the DisplayMemberPath property.</param>
protected virtual void OnDisplayMemberPathChanged(string oldDisplayMemberPath, string newDisplayMemberPath)
{
}
/// <summary>
/// The DependencyProperty for the ItemTemplate property.
/// Flags: none
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemTemplateProperty =
DependencyProperty.Register(
"ItemTemplate",
typeof(DataTemplate),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
(DataTemplate) null,
new PropertyChangedCallback(OnItemTemplateChanged)));
/// <summary>
/// ItemTemplate is the template used to display each item.
/// </summary>
[Bindable(true), CustomCategory("Content")]
public DataTemplate ItemTemplate
{
get { return (DataTemplate) GetValue(ItemTemplateProperty); }
set { SetValue(ItemTemplateProperty, value); }
}
/// <summary>
/// Called when ItemTemplateProperty is invalidated on "d."
/// </summary>
/// <param name="d">The object on which the property was invalidated.</param>
/// <param name="e">EventArgs that contains the old and new values for this property</param>
private static void OnItemTemplateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((ItemsControl) d).OnItemTemplateChanged((DataTemplate) e.OldValue, (DataTemplate) e.NewValue);
}
/// <summary>
/// This method is invoked when the ItemTemplate property changes.
/// </summary>
/// <param name="oldItemTemplate">The old value of the ItemTemplate property.</param>
/// <param name="newItemTemplate">The new value of the ItemTemplate property.</param>
protected virtual void OnItemTemplateChanged(DataTemplate oldItemTemplate, DataTemplate newItemTemplate)
{
CheckTemplateSource();
if (_itemContainerGenerator != null)
{
_itemContainerGenerator.Refresh();
}
}
/// <summary>
/// The DependencyProperty for the ItemTemplateSelector property.
/// Flags: none
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemTemplateSelectorProperty =
DependencyProperty.Register(
"ItemTemplateSelector",
typeof(DataTemplateSelector),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
(DataTemplateSelector) null,
new PropertyChangedCallback(OnItemTemplateSelectorChanged)));
/// <summary>
/// ItemTemplateSelector allows the application writer to provide custom logic
/// for choosing the template used to display each item.
/// </summary>
/// <remarks>
/// This property is ignored if <seealso cref="ItemTemplate"/> is set.
/// </remarks>
[Bindable(true), CustomCategory("Content")]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public DataTemplateSelector ItemTemplateSelector
{
get { return (DataTemplateSelector) GetValue(ItemTemplateSelectorProperty); }
set { SetValue(ItemTemplateSelectorProperty, value); }
}
/// <summary>
/// Called when ItemTemplateSelectorProperty is invalidated on "d."
/// </summary>
/// <param name="d">The object on which the property was invalidated.</param>
/// <param name="e">EventArgs that contains the old and new values for this property</param>
private static void OnItemTemplateSelectorChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((ItemsControl)d).OnItemTemplateSelectorChanged((DataTemplateSelector) e.OldValue, (DataTemplateSelector) e.NewValue);
}
/// <summary>
/// This method is invoked when the ItemTemplateSelector property changes.
/// </summary>
/// <param name="oldItemTemplateSelector">The old value of the ItemTemplateSelector property.</param>
/// <param name="newItemTemplateSelector">The new value of the ItemTemplateSelector property.</param>
protected virtual void OnItemTemplateSelectorChanged(DataTemplateSelector oldItemTemplateSelector, DataTemplateSelector newItemTemplateSelector)
{
CheckTemplateSource();
if ((_itemContainerGenerator != null) && (ItemTemplate == null))
{
_itemContainerGenerator.Refresh();
}
}
/// <summary>
/// The DependencyProperty for the ItemStringFormat property.
/// Flags: None
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemStringFormatProperty =
DependencyProperty.Register(
"ItemStringFormat",
typeof(String),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
(String) null,
new PropertyChangedCallback(OnItemStringFormatChanged)));
/// <summary>
/// ItemStringFormat is the format used to display an item (or a
/// property of an item, as declared by DisplayMemberPath) as a string.
/// This arises only when no template is available.
/// </summary>
[Bindable(true), CustomCategory("Content")]
public String ItemStringFormat
{
get { return (String) GetValue(ItemStringFormatProperty); }
set { SetValue(ItemStringFormatProperty, value); }
}
/// <summary>
/// Called when ItemStringFormatProperty is invalidated on "d."
/// </summary>
private static void OnItemStringFormatChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ItemsControl ctrl = (ItemsControl)d;
ctrl.OnItemStringFormatChanged((String) e.OldValue, (String) e.NewValue);
ctrl.UpdateDisplayMemberTemplateSelector();
}
/// <summary>
/// This method is invoked when the ItemStringFormat property changes.
/// </summary>
/// <param name="oldItemStringFormat">The old value of the ItemStringFormat property.</param>
/// <param name="newItemStringFormat">The new value of the ItemStringFormat property.</param>
protected virtual void OnItemStringFormatChanged(String oldItemStringFormat, String newItemStringFormat)
{
}
/// <summary>
/// The DependencyProperty for the ItemBindingGroup property.
/// Flags: None
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemBindingGroupProperty =
DependencyProperty.Register(
"ItemBindingGroup",
typeof(BindingGroup),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
(BindingGroup) null,
new PropertyChangedCallback(OnItemBindingGroupChanged)));
/// <summary>
/// ItemBindingGroup declares a BindingGroup to be used as a "master"
/// for the generated containers. Each container's BindingGroup is set
/// to a copy of the master, sharing the same set of validation rules,
/// but managing its own collection of bindings.
/// </summary>
[Bindable(true), CustomCategory("Content")]
public BindingGroup ItemBindingGroup
{
get { return (BindingGroup) GetValue(ItemBindingGroupProperty); }
set { SetValue(ItemBindingGroupProperty, value); }
}
/// <summary>
/// Called when ItemBindingGroupProperty is invalidated on "d."
/// </summary>
private static void OnItemBindingGroupChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ItemsControl ctrl = (ItemsControl)d;
ctrl.OnItemBindingGroupChanged((BindingGroup) e.OldValue, (BindingGroup) e.NewValue);
}
/// <summary>
/// This method is invoked when the ItemBindingGroup property changes.
/// </summary>
/// <param name="oldItemBindingGroup">The old value of the ItemBindingGroup property.</param>
/// <param name="newItemBindingGroup">The new value of the ItemBindingGroup property.</param>
protected virtual void OnItemBindingGroupChanged(BindingGroup oldItemBindingGroup, BindingGroup newItemBindingGroup)
{
}
/// <summary>
/// Throw if more than one of DisplayMemberPath, xxxTemplate and xxxTemplateSelector
/// properties are set on the given element.
/// </summary>
private void CheckTemplateSource()
{
if (string.IsNullOrEmpty(DisplayMemberPath))
{
Helper.CheckTemplateAndTemplateSelector("Item", ItemTemplateProperty, ItemTemplateSelectorProperty, this);
}
else
{
if (!(this.ItemTemplateSelector is DisplayMemberTemplateSelector))
{
throw new InvalidOperationException(SR.ItemTemplateSelectorBreaksDisplayMemberPath);
}
if (Helper.IsTemplateDefined(ItemTemplateProperty, this))
{
throw new InvalidOperationException(SR.DisplayMemberPathAndItemTemplateDefined);
}
}
}
/// <summary>
/// The DependencyProperty for the ItemContainerStyle property.
/// Flags: none
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemContainerStyleProperty =
DependencyProperty.Register(
"ItemContainerStyle",
typeof(Style),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
(Style) null,
new PropertyChangedCallback(OnItemContainerStyleChanged)));
/// <summary>
/// ItemContainerStyle is the style that is applied to the container element generated
/// for each item.
/// </summary>
[Bindable(true), Category("Content")]
public Style ItemContainerStyle
{
get { return (Style) GetValue(ItemContainerStyleProperty); }
set { SetValue(ItemContainerStyleProperty, value); }
}
/// <summary>
/// Called when ItemContainerStyleProperty is invalidated on "d."
/// </summary>
/// <param name="d">The object on which the property was invalidated.</param>
/// <param name="e">EventArgs that contains the old and new values for this property</param>
private static void OnItemContainerStyleChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((ItemsControl) d).OnItemContainerStyleChanged((Style) e.OldValue, (Style) e.NewValue);
}
/// <summary>
/// This method is invoked when the ItemContainerStyle property changes.
/// </summary>
/// <param name="oldItemContainerStyle">The old value of the ItemContainerStyle property.</param>
/// <param name="newItemContainerStyle">The new value of the ItemContainerStyle property.</param>
protected virtual void OnItemContainerStyleChanged(Style oldItemContainerStyle, Style newItemContainerStyle)
{
Helper.CheckStyleAndStyleSelector("ItemContainer", ItemContainerStyleProperty, ItemContainerStyleSelectorProperty, this);
if (_itemContainerGenerator != null)
{
_itemContainerGenerator.Refresh();
}
}
/// <summary>
/// The DependencyProperty for the ItemContainerStyleSelector property.
/// Flags: none
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemContainerStyleSelectorProperty =
DependencyProperty.Register(
"ItemContainerStyleSelector",
typeof(StyleSelector),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
(StyleSelector) null,
new PropertyChangedCallback(OnItemContainerStyleSelectorChanged)));
/// <summary>
/// ItemContainerStyleSelector allows the application writer to provide custom logic
/// to choose the style to apply to each generated container element.
/// </summary>
/// <remarks>
/// This property is ignored if <seealso cref="ItemContainerStyle"/> is set.
/// </remarks>
[Bindable(true), Category("Content")]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public StyleSelector ItemContainerStyleSelector
{
get { return (StyleSelector) GetValue(ItemContainerStyleSelectorProperty); }
set { SetValue(ItemContainerStyleSelectorProperty, value); }
}
/// <summary>
/// Called when ItemContainerStyleSelectorProperty is invalidated on "d."
/// </summary>
/// <param name="d">The object on which the property was invalidated.</param>
/// <param name="e">EventArgs that contains the old and new values for this property</param>
private static void OnItemContainerStyleSelectorChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((ItemsControl) d).OnItemContainerStyleSelectorChanged((StyleSelector) e.OldValue, (StyleSelector) e.NewValue);
}
/// <summary>
/// This method is invoked when the ItemContainerStyleSelector property changes.
/// </summary>
/// <param name="oldItemContainerStyleSelector">The old value of the ItemContainerStyleSelector property.</param>
/// <param name="newItemContainerStyleSelector">The new value of the ItemContainerStyleSelector property.</param>
protected virtual void OnItemContainerStyleSelectorChanged(StyleSelector oldItemContainerStyleSelector, StyleSelector newItemContainerStyleSelector)
{
Helper.CheckStyleAndStyleSelector("ItemContainer", ItemContainerStyleProperty, ItemContainerStyleSelectorProperty, this);
if ((_itemContainerGenerator != null) && (ItemContainerStyle == null))
{
_itemContainerGenerator.Refresh();
}
}
/// <summary>
/// Returns the ItemsControl for which element is an ItemsHost.
/// More precisely, if element is marked by setting IsItemsHost="true"
/// in the style for an ItemsControl, or if element is a panel created
/// by the ItemsPresenter for an ItemsControl, return that ItemsControl.
/// Otherwise, return null.
/// </summary>
public static ItemsControl GetItemsOwner(DependencyObject element)
{
ItemsControl container = null;
Panel panel = element as Panel;
if (panel != null && panel.IsItemsHost)
{
// see if element was generated for an ItemsPresenter
ItemsPresenter ip = ItemsPresenter.FromPanel(panel);
if (ip != null)
{
// if so use the element whose style begat the ItemsPresenter
container = ip.Owner;
}
else
{
// otherwise use element's templated parent
container = panel.TemplatedParent as ItemsControl;
}
}
return container;
}
internal static DependencyObject GetItemsOwnerInternal(DependencyObject element)
{
ItemsControl temp;
return GetItemsOwnerInternal(element, out temp);
}
/// <summary>
/// Different from public GetItemsOwner
/// Returns ip.TemplatedParent instead of ip.Owner
/// More accurate when we want to distinguish if owner is a GroupItem or ItemsControl
/// </summary>
/// <param name="element"></param>
/// <returns></returns>
internal static DependencyObject GetItemsOwnerInternal(DependencyObject element, out ItemsControl itemsControl)
{
DependencyObject container = null;
Panel panel = element as Panel;
itemsControl = null;
if (panel != null && panel.IsItemsHost)
{
// see if element was generated for an ItemsPresenter
ItemsPresenter ip = ItemsPresenter.FromPanel(panel);
if (ip != null)
{
// if so use the element whose style begat the ItemsPresenter
container = ip.TemplatedParent;
itemsControl = ip.Owner;
}
else
{
// otherwise use element's templated parent
container = panel.TemplatedParent;
itemsControl = container as ItemsControl;
}
}
return container;
}
/// <summary>
/// The DependencyProperty for the ItemsPanel property.
/// Flags: none
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ItemsPanelProperty
= DependencyProperty.Register("ItemsPanel", typeof(ItemsPanelTemplate), typeof(ItemsControl),
new FrameworkPropertyMetadata(GetDefaultItemsPanelTemplate(),
new PropertyChangedCallback(OnItemsPanelChanged)));
private static ItemsPanelTemplate GetDefaultItemsPanelTemplate()
{
ItemsPanelTemplate template = new ItemsPanelTemplate(new FrameworkElementFactory(typeof(StackPanel)));
template.Seal();
return template;
}
/// <summary>
/// ItemsPanel is the panel that controls the layout of items.
/// (More precisely, the panel that controls layout is created
/// from the template given by ItemsPanel.)
/// </summary>
[Bindable(false)]
public ItemsPanelTemplate ItemsPanel
{
get { return (ItemsPanelTemplate) GetValue(ItemsPanelProperty); }
set { SetValue(ItemsPanelProperty, value); }
}
/// <summary>
/// Called when ItemsPanelProperty is invalidated on "d."
/// </summary>
/// <param name="d">The object on which the property was invalidated.</param>
/// <param name="e">EventArgs that contains the old and new values for this property</param>
private static void OnItemsPanelChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((ItemsControl) d).OnItemsPanelChanged((ItemsPanelTemplate) e.OldValue, (ItemsPanelTemplate) e.NewValue);
}
/// <summary>
/// This method is invoked when the ItemsPanel property changes.
/// </summary>
/// <param name="oldItemsPanel">The old value of the ItemsPanel property.</param>
/// <param name="newItemsPanel">The new value of the ItemsPanel property.</param>
protected virtual void OnItemsPanelChanged(ItemsPanelTemplate oldItemsPanel, ItemsPanelTemplate newItemsPanel)
{
ItemContainerGenerator.OnPanelChanged();
}
private static readonly DependencyPropertyKey IsGroupingPropertyKey =
DependencyProperty.RegisterReadOnly("IsGrouping", typeof(bool), typeof(ItemsControl), new FrameworkPropertyMetadata(BooleanBoxes.FalseBox, new PropertyChangedCallback(OnIsGroupingChanged)));
/// <summary>
/// The DependencyProperty for the IsGrouping property.
/// </summary>
public static readonly DependencyProperty IsGroupingProperty = IsGroupingPropertyKey.DependencyProperty;
/// <summary>
/// Returns whether the control is using grouping.
/// </summary>
[Bindable(false)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public bool IsGrouping
{
get
{
return (bool)GetValue(IsGroupingProperty);
}
}
private static void OnIsGroupingChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((ItemsControl)d).OnIsGroupingChanged(e);
}
internal virtual void OnIsGroupingChanged(DependencyPropertyChangedEventArgs e)
{
ShouldCoerceScrollUnitField.SetValue(this, true);
CoerceValue(VirtualizingStackPanel.ScrollUnitProperty);
ShouldCoerceCacheSizeField.SetValue(this, true);
CoerceValue(VirtualizingPanel.CacheLengthUnitProperty);
((IContainItemStorage)this).Clear();
}
/// <summary>
/// The collection of GroupStyle objects that describes the display of
/// each level of grouping. The entry at index 0 describes the top level
/// groups, the entry at index 1 describes the next level, and so forth.
/// If there are more levels of grouping than entries in the collection,
/// the last entry is used for the extra levels.
/// </summary>
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public ObservableCollection<GroupStyle> GroupStyle
{
get { return _groupStyle; }
}
/// <summary>
/// This method is used by TypeDescriptor to determine if this property should
/// be serialized.
/// </summary>
[EditorBrowsable(EditorBrowsableState.Never)]
public bool ShouldSerializeGroupStyle()
{
return (GroupStyle.Count > 0);
}
private void OnGroupStyleChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (_itemContainerGenerator != null)
{
_itemContainerGenerator.Refresh();
}
}
/// <summary>
/// The DependencyProperty for the GroupStyleSelector property.
/// Flags: none
/// Default Value: null
/// </summary>
public static readonly DependencyProperty GroupStyleSelectorProperty
= DependencyProperty.Register("GroupStyleSelector", typeof(GroupStyleSelector), typeof(ItemsControl),
new FrameworkPropertyMetadata((GroupStyleSelector)null,
new PropertyChangedCallback(OnGroupStyleSelectorChanged)));
/// <summary>
/// GroupStyleSelector allows the app writer to provide custom selection logic
/// for a GroupStyle to apply to each group collection.
/// </summary>
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
[Bindable(true), CustomCategory("Content")]
public GroupStyleSelector GroupStyleSelector
{
get { return (GroupStyleSelector) GetValue(GroupStyleSelectorProperty); }
set { SetValue(GroupStyleSelectorProperty, value); }
}
/// <summary>
/// Called when GroupStyleSelectorProperty is invalidated on "d."
/// </summary>
/// <param name="d">The object on which the property was invalidated.</param>
/// <param name="e">EventArgs that contains the old and new values for this property</param>
private static void OnGroupStyleSelectorChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
((ItemsControl) d).OnGroupStyleSelectorChanged((GroupStyleSelector) e.OldValue, (GroupStyleSelector) e.NewValue);
}
/// <summary>
/// This method is invoked when the GroupStyleSelector property changes.
/// </summary>
/// <param name="oldGroupStyleSelector">The old value of the GroupStyleSelector property.</param>
/// <param name="newGroupStyleSelector">The new value of the GroupStyleSelector property.</param>
protected virtual void OnGroupStyleSelectorChanged(GroupStyleSelector oldGroupStyleSelector, GroupStyleSelector newGroupStyleSelector)
{
if (_itemContainerGenerator != null)
{
_itemContainerGenerator.Refresh();
}
}
/// <summary>
/// The DependencyProperty for the AlternationCount property.
/// Flags: none
/// Default Value: 0
/// </summary>
public static readonly DependencyProperty AlternationCountProperty =
DependencyProperty.Register(
"AlternationCount",
typeof(int),
typeof(ItemsControl),
new FrameworkPropertyMetadata(
(int)0,
new PropertyChangedCallback(OnAlternationCountChanged)));
/// <summary>
/// AlternationCount controls the range of values assigned to the
/// AlternationIndex property attached to each generated container. The
/// default value 0 means "do not set AlternationIndex". A positive
/// value means "assign AlternationIndex in the range [0, AlternationCount)
/// so that adjacent containers receive different values".
/// </summary>
/// <remarks>
/// By referring to AlternationIndex in a trigger or binding (typically
/// in the ItemContainerStyle), you can make the appearance of items
/// depend on their position in the display. For example, you can make
/// the background color of the items in ListBox alternate between
/// blue and white.
/// </remarks>
[Bindable(true), CustomCategory("Content")]
public int AlternationCount
{
get { return (int) GetValue(AlternationCountProperty); }
set { SetValue(AlternationCountProperty, value); }
}
/// <summary>
/// Called when AlternationCountProperty is invalidated on "d."
/// </summary>
private static void OnAlternationCountChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ItemsControl ctrl = (ItemsControl) d;
int oldAlternationCount = (int) e.OldValue;
int newAlternationCount = (int) e.NewValue;
ctrl.OnAlternationCountChanged(oldAlternationCount, newAlternationCount);
}
/// <summary>
/// This method is invoked when the AlternationCount property changes.
/// </summary>
/// <param name="oldAlternationCount">The old value of the AlternationCount property.</param>
/// <param name="newAlternationCount">The new value of the AlternationCount property.</param>
protected virtual void OnAlternationCountChanged(int oldAlternationCount, int newAlternationCount)
{
ItemContainerGenerator.ChangeAlternationCount();
}
private static readonly DependencyPropertyKey AlternationIndexPropertyKey =
DependencyProperty.RegisterAttachedReadOnly(
"AlternationIndex",
typeof(int),
typeof(ItemsControl),
new FrameworkPropertyMetadata((int)0));
/// <summary>
/// AlternationIndex is set on containers generated for an ItemsControl, when
/// the ItemsControl's AlternationCount property is positive. The AlternationIndex
/// lies in the range [0, AlternationCount), and adjacent containers always get
/// assigned different values.
/// </summary>
public static readonly DependencyProperty AlternationIndexProperty =
AlternationIndexPropertyKey.DependencyProperty;
/// <summary>
/// Static getter for the AlternationIndex attached property.
/// </summary>
public static int GetAlternationIndex(DependencyObject element)
{
ArgumentNullException.ThrowIfNull(element);
return (int)element.GetValue(AlternationIndexProperty);
}
// internal setter for AlternationIndex. This property is not settable by
// an app, only by internal code
internal static void SetAlternationIndex(DependencyObject d, int value)
{
d.SetValue(AlternationIndexPropertyKey, value);
}
// internal clearer for AlternationIndex. This property is not settable by
// an app, only by internal code
internal static void ClearAlternationIndex(DependencyObject d)
{
d.ClearValue(AlternationIndexPropertyKey);
}
/// <summary>
/// The DependencyProperty for the IsTextSearchEnabled property.
/// Default Value: false
/// </summary>
public static readonly DependencyProperty IsTextSearchEnabledProperty =
DependencyProperty.Register(
"IsTextSearchEnabled",
typeof(bool),
typeof(ItemsControl),
new FrameworkPropertyMetadata(BooleanBoxes.FalseBox));
/// <summary>
/// Whether TextSearch is enabled or not on this ItemsControl
/// </summary>
public bool IsTextSearchEnabled
{
get { return (bool) GetValue(IsTextSearchEnabledProperty); }
set { SetValue(IsTextSearchEnabledProperty, BooleanBoxes.Box(value)); }
}
/// <summary>
/// The DependencyProperty for the IsTextSearchCaseSensitive property.
/// Default Value: false
/// </summary>
public static readonly DependencyProperty IsTextSearchCaseSensitiveProperty =
DependencyProperty.Register(
"IsTextSearchCaseSensitive",
typeof(bool),
typeof(ItemsControl),
new FrameworkPropertyMetadata(BooleanBoxes.FalseBox));
/// <summary>
/// Whether TextSearch is case sensitive or not on this ItemsControl
/// </summary>
public bool IsTextSearchCaseSensitive
{
get { return (bool) GetValue(IsTextSearchCaseSensitiveProperty); }
set { SetValue(IsTextSearchCaseSensitiveProperty, BooleanBoxes.Box(value)); }
}
#endregion
#region Mapping methods
///<summary>
/// Return the ItemsControl that owns the given container element
///</summary>
public static ItemsControl ItemsControlFromItemContainer(DependencyObject container)
{
UIElement ui = container as UIElement;
if (ui == null)
return null;
// ui appeared in items collection
ItemsControl ic = LogicalTreeHelper.GetParent(ui) as ItemsControl;
if (ic != null)
{
// this is the right ItemsControl as long as the item
// is (or is eligible to be) its own container
IGeneratorHost host = ic as IGeneratorHost;
if (host.IsItemItsOwnContainer(ui))
return ic;
else
return null;
}
ui = VisualTreeHelper.GetParent(ui) as UIElement;
return ItemsControl.GetItemsOwner(ui);
}
///<summary>
/// Return the container that owns the given element. If itemsControl
/// is not null, return a container that belongs to the given ItemsControl.
/// If itemsControl is null, return the closest container belonging to
/// any ItemsControl. Return null if no such container exists.
///</summary>
public static DependencyObject ContainerFromElement(ItemsControl itemsControl, DependencyObject element)
{
ArgumentNullException.ThrowIfNull(element);
// if the element is itself the desired container, return it
if (IsContainerForItemsControl(element, itemsControl))
{
return element;
}
// start the tree walk at the element's parent
FrameworkObject fo = new FrameworkObject(element);
fo.Reset(fo.GetPreferVisualParent(true).DO);
// walk up, stopping when we reach the desired container
while (fo.DO != null)
{
if (IsContainerForItemsControl(fo.DO, itemsControl))
{
break;
}
fo.Reset(fo.PreferVisualParent.DO);
}
return fo.DO;
}
///<summary>
/// Return the container belonging to the current ItemsControl that owns
/// the given container element. Return null if no such container exists.
///</summary>
public DependencyObject ContainerFromElement(DependencyObject element)
{
return ContainerFromElement(this, element);
}
// helper method used by ContainerFromElement
private static bool IsContainerForItemsControl(DependencyObject element, ItemsControl itemsControl)
{
// is the element a container?
if (element.ContainsValue(ItemContainerGenerator.ItemForItemContainerProperty))
{
// does the element belong to the itemsControl?
if (itemsControl == null || itemsControl == ItemsControlFromItemContainer(element))
{
return true;
}
}
return false;
}
#endregion Mapping methods
#region IAddChild
///<summary>
/// Called to Add the object as a Child.
///</summary>
///<param name="value">
/// Object to add as a child
///</param>
void IAddChild.AddChild(Object value)
{
AddChild(value);
}
/// <summary>
/// Add an object child to this control
/// </summary>
protected virtual void AddChild(object value)
{
Items.Add(value);
}
///<summary>
/// Called when text appears under the tag in markup
///</summary>
///<param name="text">
/// Text to Add to the Object
///</param>
void IAddChild.AddText(string text)
{
AddText(text);
}
/// <summary>
/// Add a text string to this control
/// </summary>
protected virtual void AddText(string text)
{
Items.Add(text);
}
#endregion
#region IGeneratorHost
//------------------------------------------------------
//
// Interface - IGeneratorHost
//
//------------------------------------------------------
/// <summary>
/// The view of the data
/// </summary>
ItemCollection IGeneratorHost.View
{
get { return Items; }
}
/// <summary>
/// Return true if the item is (or is eligible to be) its own ItemContainer
/// </summary>
bool IGeneratorHost.IsItemItsOwnContainer(object item)
{
return IsItemItsOwnContainer(item);
}
/// <summary>
/// Return the element used to display the given item
/// </summary>
DependencyObject IGeneratorHost.GetContainerForItem(object item)
{
DependencyObject container;
// use the item directly, if possible (bug 870672)
if (IsItemItsOwnContainerOverride(item))
container = item as DependencyObject;
else
container = GetContainerForItemOverride();
// the container might have a parent from a previous
// generation (bug 873118). If so, clean it up before using it again.
//
// Note: This assumes the container is about to be added to a new parent,
// according to the ItemsControl/Generator/Container pattern.
// If someone calls the generator and doesn't add the container to
// a visual parent, unexpected things might happen.
Visual visual = container as Visual;
if (visual != null)
{
Visual parent = VisualTreeHelper.GetParent(visual) as Visual;
if (parent != null)
{
Invariant.Assert(parent is FrameworkElement, SR.ItemsControl_ParentNotFrameworkElement);
Panel p = parent as Panel;
if (p != null && (visual is UIElement))
{
p.Children.RemoveNoVerify((UIElement)visual);
}
else
{
((FrameworkElement)parent).TemplateChild = null;
}
}
}
return container;
}
/// <summary>
/// Prepare the element to act as the ItemContainer for the corresponding item.
/// </summary>
void IGeneratorHost.PrepareItemContainer(DependencyObject container, object item)
{
// GroupItems are special - their information comes from a different place
GroupItem groupItem = container as GroupItem;
if (groupItem != null)
{
groupItem.PrepareItemContainer(item, this);
return;
}
if (ShouldApplyItemContainerStyle(container, item))
{
// apply the ItemContainer style (if any)
ApplyItemContainerStyle(container, item);
}
// forward ItemTemplate, et al.
PrepareContainerForItemOverride(container, item);
// set up the binding group
if (!Helper.HasUnmodifiedDefaultValue(this, ItemBindingGroupProperty) &&
Helper.HasUnmodifiedDefaultOrInheritedValue(container, FrameworkElement.BindingGroupProperty))
{
BindingGroup itemBindingGroup = ItemBindingGroup;
BindingGroup containerBindingGroup =
(itemBindingGroup != null) ? new BindingGroup(itemBindingGroup)
: null;
container.SetValue(FrameworkElement.BindingGroupProperty, containerBindingGroup);
}
if (container == item && TraceData.IsEnabled)
{
// issue a message if there's an ItemTemplate(Selector) for "direct" items
// The ItemTemplate isn't used, which may confuse the user (bug 991101).
if (ItemTemplate != null || ItemTemplateSelector != null)
{
TraceData.TraceAndNotify(TraceEventType.Error, TraceData.ItemTemplateForDirectItem, null,
traceParameters: new object[] { AvTrace.TypeName(item) });
}
}
TreeViewItem treeViewItem = container as TreeViewItem;
if (treeViewItem != null)
{
treeViewItem.PrepareItemContainer(item, this);
}
}
/// <summary>
/// Undo any initialization done on the element during GetContainerForItem and PrepareItemContainer
/// </summary>
void IGeneratorHost.ClearContainerForItem(DependencyObject container, object item)
{
// This method no longer does most of the work it used to (bug 1445288).
// It is called when a container is removed from the tree; such a
// container will be GC'd soon, so there's no point in changing
// its properties.
//
// We still call the override method, to give subclasses a chance
// to clean up anything they may have done during Prepare (bug 1561206).
GroupItem groupItem = container as GroupItem;
if (groupItem == null)
{
ClearContainerForItemOverride(container, item);
TreeViewItem treeViewItem = container as TreeViewItem;
if (treeViewItem != null)
{
treeViewItem.ClearItemContainer(item, this);
}
}
else
{
// GroupItems are special - their information comes from a different place
// Recursively clear the sub-generators, so that ClearContainerForItemOverride
// is called on the bottom-level containers.
groupItem.ClearItemContainer(item, this);
}
}
/// <summary>
/// Determine if the given element was generated for this host as an ItemContainer.
/// </summary>
bool IGeneratorHost.IsHostForItemContainer(DependencyObject container)
{
// If ItemsControlFromItemContainer can determine who owns the element,
// use its decision.
ItemsControl ic = ItemsControlFromItemContainer(container);
if (ic != null)
return (ic == this);
// If the element is in my items view, and if it can be its own ItemContainer,
// it's mine. Contains may be expensive, so we avoid calling it in cases
// where we already know the answer - namely when the element has a
// logical parent (ItemsControlFromItemContainer handles this case). This
// leaves only those cases where the element belongs to my items
// without having a logical parent (e.g. via ItemsSource) and without
// having been generated yet. HasItem indicates if anything has been generated.
DependencyObject parent = LogicalTreeHelper.GetParent(container);
if (parent == null)
{
return IsItemItsOwnContainerOverride(container) &&
HasItems && Items.Contains(container);
}
// Otherwise it's not mine
return false;
}
/// <summary>
/// Return the GroupStyle (if any) to use for the given group at the given level.
/// </summary>
GroupStyle IGeneratorHost.GetGroupStyle(CollectionViewGroup group, int level)
{
GroupStyle result = null;
// a. Use global selector
if (GroupStyleSelector != null)
{
result = GroupStyleSelector(group, level);
}
// b. lookup in GroupStyle list
if (result == null)
{
// use last entry for all higher levels
if (level >= GroupStyle.Count)
{
level = GroupStyle.Count - 1;
}
if (level >= 0)
{
result = GroupStyle[level];
}
}
return result;
}
/// <summary>
/// Communicates to the host that the generator is using grouping.
/// </summary>
void IGeneratorHost.SetIsGrouping(bool isGrouping)
{
SetValue(IsGroupingPropertyKey, BooleanBoxes.Box(isGrouping));
}
/// <summary>
/// The AlternationCount
/// <summary>
int IGeneratorHost.AlternationCount { get { return AlternationCount; } }
#endregion IGeneratorHost
#region ISupportInitialize
/// <summary>
/// Initialization of this element is about to begin
/// </summary>
public override void BeginInit()
{
base.BeginInit();
if (_items != null)
{
_items.BeginInit();
}
}
/// <summary>
/// Initialization of this element has completed
/// </summary>
public override void EndInit()
{
if (IsInitPending)
{
if (_items != null)
{
_items.EndInit();
}
base.EndInit();
}
}
private bool IsInitPending
{
get
{
return ReadInternalFlag(InternalFlags.InitPending);
}
}
#endregion
#region Protected Methods
/// <summary>
/// Return true if the item is (or should be) its own item container
/// </summary>
public bool IsItemItsOwnContainer(object item)
{
return IsItemItsOwnContainerOverride(item);
}
/// <summary>
/// Return true if the item is (or should be) its own item container
/// </summary>
protected virtual bool IsItemItsOwnContainerOverride(object item)
{
return (item is UIElement);
}
/// <summary> Create or identify the element used to display the given item. </summary>
protected virtual DependencyObject GetContainerForItemOverride()
{
return new ContentPresenter();
}
/// <summary>
/// Prepare the element to display the item. This may involve
/// applying styles, setting bindings, etc.
/// </summary>
protected virtual void PrepareContainerForItemOverride(DependencyObject element, object item)
{
// Each type of "ItemContainer" element may require its own initialization.
// We use explicit polymorphism via internal methods for this.
//
// Another way would be to define an interface IGeneratedItemContainer with
// corresponding virtual "core" methods. Base classes (ContentControl,
// ItemsControl, ContentPresenter) would implement the interface
// and forward the work to subclasses via the "core" methods.
//
// While this is better from an OO point of view, and extends to
// 3rd-party elements used as containers, it exposes more public API.
// Management considers this undesirable, hence the following rather
// inelegant code.
HeaderedContentControl hcc;
ContentControl cc;
ContentPresenter cp;
ItemsControl ic;
HeaderedItemsControl hic;
if ((hcc = element as HeaderedContentControl) != null)
{
hcc.PrepareHeaderedContentControl(item, ItemTemplate, ItemTemplateSelector, ItemStringFormat);
}
else if ((cc = element as ContentControl) != null)
{
cc.PrepareContentControl(item, ItemTemplate, ItemTemplateSelector, ItemStringFormat);
}
else if ((cp = element as ContentPresenter) != null)
{
cp.PrepareContentPresenter(item, ItemTemplate, ItemTemplateSelector, ItemStringFormat);
}
else if ((hic = element as HeaderedItemsControl) != null)
{
hic.PrepareHeaderedItemsControl(item, this);
}
else if ((ic = element as ItemsControl) != null)
{
if (ic != this)
{
ic.PrepareItemsControl(item, this);
}
}
}
/// <summary>
/// Undo the effects of PrepareContainerForItemOverride.
/// </summary>
protected virtual void ClearContainerForItemOverride(DependencyObject element, object item)
{
HeaderedContentControl hcc;
ContentControl cc;
ContentPresenter cp;
ItemsControl ic;
HeaderedItemsControl hic;
if ((hcc = element as HeaderedContentControl) != null)
{
hcc.ClearHeaderedContentControl(item);
}
else if ((cc = element as ContentControl) != null)
{
cc.ClearContentControl(item);
}
else if ((cp = element as ContentPresenter) != null)
{
cp.ClearContentPresenter(item);
}
else if ((hic = element as HeaderedItemsControl) != null)
{
hic.ClearHeaderedItemsControl(item);
}
else if ((ic = element as ItemsControl) != null)
{
if (ic != this)
{
ic.ClearItemsControl(item);
}
}
}
/// <summary>
/// Called when a TextInput event is received.
/// </summary>
/// <param name="e"></param>
protected override void OnTextInput(TextCompositionEventArgs e)
{
base.OnTextInput(e);
// Only handle text from ourselves or an item container
if (!String.IsNullOrEmpty(e.Text) && IsTextSearchEnabled &&
(e.OriginalSource == this || ItemsControlFromItemContainer(e.OriginalSource as DependencyObject) == this))
{
TextSearch instance = TextSearch.EnsureInstance(this);
if (instance != null)
{
instance.DoSearch(e.Text);
// Note: we always want to handle the event to denote that we
// actually did something. We wouldn't want an AccessKey
// to get invoked just because there wasn't a match here.
e.Handled = true;
}
}
}
/// <summary>
/// Called when a KeyDown event is received.
/// </summary>
/// <param name="e"></param>
protected override void OnKeyDown(KeyEventArgs e)
{
base.OnKeyDown(e);
if (IsTextSearchEnabled)
{
// If the pressed the backspace key, delete the last character
// in the TextSearch current prefix.
if (e.Key == Key.Back)
{
TextSearch instance = TextSearch.EnsureInstance(this);
if (instance != null)
{
instance.DeleteLastCharacter();
}
}
}
}
internal override void OnTemplateChangedInternal(FrameworkTemplate oldTemplate, FrameworkTemplate newTemplate)
{
// Forget about the old ItemsHost we had when the style changes
_itemsHost = null;
_scrollHost = null;
WriteControlFlag(ControlBoolFlags.ScrollHostValid, false);
base.OnTemplateChangedInternal(oldTemplate, newTemplate);
}
/// <summary>
/// Determine whether the ItemContainerStyle/StyleSelector should apply to the container
/// </summary>
/// <returns>true if the ItemContainerStyle should apply to the item</returns>
protected virtual bool ShouldApplyItemContainerStyle(DependencyObject container, object item)
{
return true;
}
#endregion
//------------------------------------------------------
//
// Internal methods
//
//------------------------------------------------------
#region Internal Methods
/// <summary>
/// Prepare to display the item.
/// </summary>
internal void PrepareItemsControl(object item, ItemsControl parentItemsControl)
{
if (item != this)
{
// copy templates and styles from parent ItemsControl
DataTemplate itemTemplate = parentItemsControl.ItemTemplate;
DataTemplateSelector itemTemplateSelector = parentItemsControl.ItemTemplateSelector;
string itemStringFormat = parentItemsControl.ItemStringFormat;
Style itemContainerStyle = parentItemsControl.ItemContainerStyle;
StyleSelector itemContainerStyleSelector = parentItemsControl.ItemContainerStyleSelector;
int alternationCount = parentItemsControl.AlternationCount;
BindingGroup itemBindingGroup = parentItemsControl.ItemBindingGroup;
if (itemTemplate != null)
{
SetValue(ItemTemplateProperty, itemTemplate);
}
if (itemTemplateSelector != null)
{
SetValue(ItemTemplateSelectorProperty, itemTemplateSelector);
}
if (itemStringFormat != null &&
Helper.HasDefaultValue(this, ItemStringFormatProperty))
{
SetValue(ItemStringFormatProperty, itemStringFormat);
}
if (itemContainerStyle != null &&
Helper.HasDefaultValue(this, ItemContainerStyleProperty))
{
SetValue(ItemContainerStyleProperty, itemContainerStyle);
}
if (itemContainerStyleSelector != null &&
Helper.HasDefaultValue(this, ItemContainerStyleSelectorProperty))
{
SetValue(ItemContainerStyleSelectorProperty, itemContainerStyleSelector);
}
if (alternationCount != 0 &&
Helper.HasDefaultValue(this, AlternationCountProperty))
{
SetValue(AlternationCountProperty, alternationCount);
}
if (itemBindingGroup != null &&
Helper.HasDefaultValue(this, ItemBindingGroupProperty))
{
SetValue(ItemBindingGroupProperty, itemBindingGroup);
}
}
}
/// <summary>
/// Undo the effect of PrepareItemsControl.
/// </summary>
internal void ClearItemsControl(object item)
{
if (item != this)
{
// nothing to do
}
}
/// <summary>
/// Bringing the item passed as arg into view. If item is virtualized it will become realized.
/// </summary>
/// <param name="arg"></param>
/// <returns></returns>
internal object OnBringItemIntoView(object arg)
{
ItemInfo info = arg as ItemInfo;
if (info == null)
{
info = NewItemInfo(arg);
}
return OnBringItemIntoView(info);
}
internal object OnBringItemIntoView(ItemInfo info)
{
FrameworkElement element = info.Container as FrameworkElement;
if (element != null)
{
element.BringIntoView();
}
else if ((info = LeaseItemInfo(info, true)).Index >= 0)
{
// We might be virtualized, try to de-virtualize the item.
// Note: There is opportunity here to make a public OM.
//
// Call UpdateLayout first, in case there is a pending Measure
// that replaces the ItemsHost with a different panel. We should
// forward the request to the correct panel, of course.
if (!FrameworkCompatibilityPreferences.GetVSP45Compat())
{
UpdateLayout();
}
VirtualizingPanel itemsHost = ItemsHost as VirtualizingPanel;
if (itemsHost != null)
{
itemsHost.BringIndexIntoView(info.Index);
}
}
return null;
}
internal Panel ItemsHost
{
get
{
return _itemsHost;
}
set { _itemsHost = value; }
}
#region Keyboard Navigation
internal bool NavigateByLine(FocusNavigationDirection direction, ItemNavigateArgs itemNavigateArgs)
{
DependencyObject startingElement = Keyboard.FocusedElement as DependencyObject;
if (!FrameworkAppContextSwitches.KeyboardNavigationFromHyperlinkInItemsControlIsNotRelativeToFocusedElement)
{
while (startingElement != null && !(startingElement is FrameworkElement))
{
// if focus is on a non-FE (e.g. Hyperlink), start the navigation
// from its nearest FE ancestor
startingElement = KeyboardNavigation.GetParent(startingElement) as DependencyObject;
}
}
return NavigateByLine(FocusedInfo, startingElement as FrameworkElement, direction, itemNavigateArgs);
}
internal void PrepareNavigateByLine(ItemInfo startingInfo,
FrameworkElement startingElement,
FocusNavigationDirection direction,
ItemNavigateArgs itemNavigateArgs,
out FrameworkElement container)
{
container = null;
if (ItemsHost == null)
{
return;
}
// If the focused container/item has been scrolled out of view and they want to
// start navigating again, scroll it back into view.
if (startingElement != null)
{
MakeVisible(startingElement, direction, false);
}
else
{
MakeVisible(startingInfo, direction, out startingElement);
}
object startingItem = (startingInfo != null) ? startingInfo.Item : null;
// When we get here if startingItem is non-null, it must be on the visible page.
NavigateByLineInternal(startingItem,
direction,
startingElement,
itemNavigateArgs,
false /*shouldFocus*/,
out container);
}
internal bool NavigateByLine(ItemInfo startingInfo,
FocusNavigationDirection direction,
ItemNavigateArgs itemNavigateArgs)
{
return NavigateByLine(startingInfo, null, direction, itemNavigateArgs);
}
internal bool NavigateByLine(ItemInfo startingInfo,
FrameworkElement startingElement,
FocusNavigationDirection direction,
ItemNavigateArgs itemNavigateArgs)
{
if (ItemsHost == null)
{
return false;
}
// If the focused container/item has been scrolled out of view and they want to
// start navigating again, scroll it back into view.
if (startingElement != null)
{
MakeVisible(startingElement, direction, false);
}
else
{
MakeVisible(startingInfo, direction, out startingElement);
}
object startingItem = (startingInfo != null) ? startingInfo.Item : null;
// When we get here if startingItem is non-null, it must be on the visible page.
FrameworkElement container;
return NavigateByLineInternal(startingItem,
direction,
startingElement,
itemNavigateArgs,
true /*shouldFocus*/,
out container);
}
private bool NavigateByLineInternal(object startingItem,
FocusNavigationDirection direction,
FrameworkElement startingElement,
ItemNavigateArgs itemNavigateArgs,
bool shouldFocus,
out FrameworkElement container)
{
container = null;
//
// If there is no starting item, just navigate to the first item.
//
if (startingItem == null &&
(startingElement == null || startingElement == this))
{
return NavigateToStartInternal(itemNavigateArgs, shouldFocus, out container);
}
else
{
FrameworkElement nextElement = null;
//
// If the container isn't there, it might have been degenerated or
// it might have been scrolled out of view. Either way, we
// should start navigation from the ItemsHost b/c we know it
// is visible.
// The generator could have given us an element which isn't
// actually visually connected. In this case we should use
// the ItemsHost as well.
//
if (startingElement == null || !ItemsHost.IsAncestorOf(startingElement))
{
//
// Bug 991220 makes it so that we have to start from the ScrollHost.
// If we try to start from the ItemsHost it will always skip the first item.
//
startingElement = ScrollHost;
}
else
{
// if the starting element is with in an element with contained or cycle scope
// then let the default keyboard navigation logic kick in.
DependencyObject startingParent = VisualTreeHelper.GetParent(startingElement);
while (startingParent != null &&
startingParent != ItemsHost)
{
KeyboardNavigationMode mode = KeyboardNavigation.GetDirectionalNavigation(startingParent);
if (mode == KeyboardNavigationMode.Contained ||
mode == KeyboardNavigationMode.Cycle)
{
return false;
}
startingParent = VisualTreeHelper.GetParent(startingParent);
}
}
bool isHorizontal = (ItemsHost != null && ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
bool treeViewNavigation = (this is TreeView);
nextElement = KeyboardNavigation.Current.PredictFocusedElement(startingElement,
direction,
treeViewNavigation) as FrameworkElement;
if (ScrollHost != null)
{
bool didScroll = false;
FrameworkElement viewport = GetViewportElement();
VirtualizingPanel virtualizingPanel = ItemsHost as VirtualizingPanel;
bool isCycle = KeyboardNavigation.GetDirectionalNavigation(this) == KeyboardNavigationMode.Cycle;
while (true)
{
if (nextElement != null)
{
if (virtualizingPanel != null &&
ScrollHost.CanContentScroll &&
VirtualizingPanel.GetIsVirtualizing(this))
{
Rect currentRect;
ElementViewportPosition elementPosition = GetElementViewportPosition(viewport,
TryGetTreeViewItemHeader(nextElement) as FrameworkElement,
direction,
false /*fullyVisible*/,
out currentRect);
if (elementPosition == ElementViewportPosition.CompletelyInViewport ||
elementPosition == ElementViewportPosition.PartiallyInViewport)
{
if (!isCycle)
{
break;
}
else
{
Rect startingRect;
GetElementViewportPosition(viewport,
startingElement,
direction,
false /*fullyVisible*/,
out startingRect);
bool isInDirection = IsInDirectionForLineNavigation(startingRect, currentRect, direction, isHorizontal);
if (isInDirection)
{
// If the next element in cycle mode is in direction
// then this is a valid candidate, If not then try
// scrolling.
break;
}
}
}
}
else
{
break;
}
//
// We are disregarding the previously predicted element because
// it is outside the viewport extents of a VirtualizingPanel
//
nextElement = null;
}
double oldHorizontalOffset = ScrollHost.HorizontalOffset;
double oldVerticalOffset = ScrollHost.VerticalOffset;
switch (direction)
{
case FocusNavigationDirection.Down:
{
didScroll = true;
if (isHorizontal)
{
ScrollHost.LineRight();
}
else
{
ScrollHost.LineDown();
}
}
break;
case FocusNavigationDirection.Up:
{
didScroll = true;
if (isHorizontal)
{
ScrollHost.LineLeft();
}
else
{
ScrollHost.LineUp();
}
}
break;
}
ScrollHost.UpdateLayout();
// If offset does not change, or if offset goes out of range - exit the loop.
// The out-of-range check is to defend against buggy implementations of
// IScrollInfo; WPF's implementations always leave the
// offset within range.
if ((DoubleUtil.AreClose(oldHorizontalOffset, ScrollHost.HorizontalOffset) &&
DoubleUtil.AreClose(oldVerticalOffset, ScrollHost.VerticalOffset))
|| (direction == FocusNavigationDirection.Down &&
(ScrollHost.VerticalOffset > ScrollHost.ExtentHeight ||
ScrollHost.HorizontalOffset > ScrollHost.ExtentWidth))
|| (direction == FocusNavigationDirection.Up &&
(ScrollHost.VerticalOffset < 0.0 ||
ScrollHost.HorizontalOffset < 0.0)))
{
if (isCycle)
{
if (direction == FocusNavigationDirection.Up)
{
// If scrollviewer cannot be scrolled any further,
// then cycle and navigate to end.
return NavigateToEndInternal(itemNavigateArgs, true, out container);
}
else if (direction == FocusNavigationDirection.Down)
{
// If scrollviewer cannot be scrolled any further,
// then cycle and navigate to start.
return NavigateToStartInternal(itemNavigateArgs, true, out container);
}
}
break;
}
nextElement = KeyboardNavigation.Current.PredictFocusedElement(startingElement,
direction,
treeViewNavigation) as FrameworkElement;
}
if (didScroll && nextElement != null && ItemsHost.IsAncestorOf(nextElement))
{
// Adjust offset so that the nextElement is aligned to the edge
AdjustOffsetToAlignWithEdge(nextElement, direction);
}
}
// We can only navigate there if the target element is in the items host.
if ((nextElement != null) && (ItemsHost.IsAncestorOf(nextElement)))
{
ItemsControl itemsControl = null;
object nextItem = GetEncapsulatingItem(nextElement, out container, out itemsControl);
container = nextElement;
if (shouldFocus)
{
if (nextItem == DependencyProperty.UnsetValue || nextItem is CollectionViewGroupInternal)
{
return nextElement.Focus();
}
else if (itemsControl != null)
{
return itemsControl.FocusItem(NewItemInfo(nextItem, container), itemNavigateArgs);
}
}
else
{
return false;
}
}
}
return false;
}
internal void PrepareToNavigateByPage(ItemInfo startingInfo,
FrameworkElement startingElement,
FocusNavigationDirection direction,
ItemNavigateArgs itemNavigateArgs,
out FrameworkElement container)
{
container = null;
if (ItemsHost == null)
{
return;
}
// If the focused container/item has been scrolled out of view and they want to
// start navigating again, scroll it back into view.
if (startingElement != null)
{
MakeVisible(startingElement, direction, /*alwaysAtTopOfViewport*/ false);
}
else
{
MakeVisible(startingInfo, direction, out startingElement);
}
object startingItem = (startingInfo != null) ? startingInfo.Item : null;
// When we get here if startingItem is non-null, it must be on the visible page.
NavigateByPageInternal(startingItem,
direction,
startingElement,
itemNavigateArgs,
false /*shouldFocus*/,
out container);
}
internal bool NavigateByPage(FocusNavigationDirection direction, ItemNavigateArgs itemNavigateArgs)
{
return NavigateByPage(FocusedInfo, Keyboard.FocusedElement as FrameworkElement, direction, itemNavigateArgs);
}
internal bool NavigateByPage(
ItemInfo startingInfo,
FocusNavigationDirection direction,
ItemNavigateArgs itemNavigateArgs)
{
return NavigateByPage(startingInfo, null, direction, itemNavigateArgs);
}
internal bool NavigateByPage(
ItemInfo startingInfo,
FrameworkElement startingElement,
FocusNavigationDirection direction,
ItemNavigateArgs itemNavigateArgs)
{
if (ItemsHost == null)
{
return false;
}
// If the focused container/item has been scrolled out of view and they want to
// start navigating again, scroll it back into view.
if (startingElement != null)
{
MakeVisible(startingElement, direction, /*alwaysAtTopOfViewport*/ false);
}
else
{
MakeVisible(startingInfo, direction, out startingElement);
}
object startingItem = (startingInfo != null) ? startingInfo.Item : null;
// When we get here if startingItem is non-null, it must be on the visible page.
FrameworkElement container;
return NavigateByPageInternal(startingItem,
direction,
startingElement,
itemNavigateArgs,
true /*shouldFocus*/,
out container);
}
private bool NavigateByPageInternal(object startingItem,
FocusNavigationDirection direction,
FrameworkElement startingElement,
ItemNavigateArgs itemNavigateArgs,
bool shouldFocus,
out FrameworkElement container)
{
container = null;
//
// Move to the last guy on the page if we're not already there.
//
if (startingItem == null &&
(startingElement == null || startingElement == this))
{
return NavigateToFirstItemOnCurrentPage(startingItem, direction, itemNavigateArgs, shouldFocus, out container);
}
else
{
//
// See if the currently focused guy is the first or last one one the page
//
FrameworkElement firstElement;
object firstItem = GetFirstItemOnCurrentPage(startingElement, direction, out firstElement);
if ((object.Equals(startingItem, firstItem) ||
object.Equals(startingElement, firstElement)) &&
ScrollHost != null)
{
bool isHorizontal = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
do
{
double oldHorizontalOffset = ScrollHost.HorizontalOffset;
double oldVerticalOffset = ScrollHost.VerticalOffset;
switch (direction)
{
case FocusNavigationDirection.Up:
{
if (isHorizontal)
{
ScrollHost.PageLeft();
}
else
{
ScrollHost.PageUp();
}
}
break;
case FocusNavigationDirection.Down:
{
if (isHorizontal)
{
ScrollHost.PageRight();
}
else
{
ScrollHost.PageDown();
}
}
break;
}
ScrollHost.UpdateLayout();
// If offset does not change - exit the loop
if (DoubleUtil.AreClose(oldHorizontalOffset, ScrollHost.HorizontalOffset) &&
DoubleUtil.AreClose(oldVerticalOffset, ScrollHost.VerticalOffset))
break;
firstItem = GetFirstItemOnCurrentPage(startingElement, direction, out firstElement);
}
while (firstItem == DependencyProperty.UnsetValue);
}
container = firstElement;
if (shouldFocus)
{
if (firstElement != null &&
(firstItem == DependencyProperty.UnsetValue || firstItem is CollectionViewGroupInternal))
{
return firstElement.Focus();
}
else
{
ItemsControl itemsControl = GetEncapsulatingItemsControl(firstElement);
if (itemsControl != null)
{
return itemsControl.FocusItem(NewItemInfo(firstItem, firstElement), itemNavigateArgs);
}
}
}
}
return false;
}
internal void NavigateToStart(ItemNavigateArgs itemNavigateArgs)
{
FrameworkElement container;
NavigateToStartInternal(itemNavigateArgs, true /*shouldFocus*/, out container);
}
internal bool NavigateToStartInternal(ItemNavigateArgs itemNavigateArgs, bool shouldFocus, out FrameworkElement container)
{
container = null;
if (ItemsHost != null)
{
if (ScrollHost != null)
{
double oldHorizontalOffset = 0.0;
double oldVerticalOffset = 0.0;
bool isHorizontal = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
do
{
oldHorizontalOffset = ScrollHost.HorizontalOffset;
oldVerticalOffset = ScrollHost.VerticalOffset;
if (isHorizontal)
{
ScrollHost.ScrollToLeftEnd();
}
else
{
ScrollHost.ScrollToTop();
}
// Wait for layout
ItemsHost.UpdateLayout();
}
// If offset does not change - exit the loop
while (!DoubleUtil.AreClose(oldHorizontalOffset, ScrollHost.HorizontalOffset) ||
!DoubleUtil.AreClose(oldVerticalOffset, ScrollHost.VerticalOffset));
}
FrameworkElement firstElement;
FrameworkElement hopefulFirstElement = FindEndFocusableLeafContainer(ItemsHost, false /*last*/);
object firstItem = GetFirstItemOnCurrentPage(hopefulFirstElement,
FocusNavigationDirection.Up,
out firstElement);
container = firstElement;
if (shouldFocus)
{
if (firstElement != null &&
(firstItem == DependencyProperty.UnsetValue || firstItem is CollectionViewGroupInternal))
{
return firstElement.Focus();
}
else
{
ItemsControl itemsControl = GetEncapsulatingItemsControl(firstElement);
if (itemsControl != null)
{
return itemsControl.FocusItem(NewItemInfo(firstItem, firstElement), itemNavigateArgs);
}
}
}
}
return false;
}
internal void NavigateToEnd(ItemNavigateArgs itemNavigateArgs)
{
FrameworkElement container;
NavigateToEndInternal(itemNavigateArgs, true /*shouldFocus*/, out container);
}
internal bool NavigateToEndInternal(ItemNavigateArgs itemNavigateArgs, bool shouldFocus, out FrameworkElement container)
{
container = null;
if (ItemsHost != null)
{
if (ScrollHost != null)
{
double oldHorizontalOffset = 0.0;
double oldVerticalOffset = 0.0;
bool isHorizontal = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
do
{
oldHorizontalOffset = ScrollHost.HorizontalOffset;
oldVerticalOffset = ScrollHost.VerticalOffset;
if (isHorizontal)
{
ScrollHost.ScrollToRightEnd();
}
else
{
ScrollHost.ScrollToBottom();
}
// Wait for layout
ItemsHost.UpdateLayout();
}
// If offset does not change - exit the loop
while (!DoubleUtil.AreClose(oldHorizontalOffset, ScrollHost.HorizontalOffset) ||
!DoubleUtil.AreClose(oldVerticalOffset, ScrollHost.VerticalOffset));
}
FrameworkElement lastElement;
FrameworkElement hopefulLastElement = FindEndFocusableLeafContainer(ItemsHost, true /*last*/);
object lastItem = GetFirstItemOnCurrentPage(hopefulLastElement,
FocusNavigationDirection.Down,
out lastElement);
container = lastElement;
if (shouldFocus)
{
if (lastElement != null &&
(lastItem == DependencyProperty.UnsetValue || lastItem is CollectionViewGroupInternal))
{
return lastElement.Focus();
}
else
{
ItemsControl itemsControl = GetEncapsulatingItemsControl(lastElement);
if (itemsControl != null)
{
return itemsControl.FocusItem(NewItemInfo(lastItem, lastElement), itemNavigateArgs);
}
}
}
}
return false;
}
private FrameworkElement FindEndFocusableLeafContainer(Panel itemsHost, bool last)
{
if (itemsHost == null)
{
return null;
}
UIElementCollection children = itemsHost.Children;
if (children != null)
{
int count = children.Count;
int i = (last ? count - 1 : 0);
int incr = (last ? -1 : 1);
while (i >= 0 && i < count)
{
FrameworkElement fe = children[i] as FrameworkElement;
if (fe != null)
{
ItemsControl itemsControl = fe as ItemsControl;
FrameworkElement result = null;
if (itemsControl != null)
{
if (itemsControl.ItemsHost != null)
{
result = FindEndFocusableLeafContainer(itemsControl.ItemsHost, last);
}
}
else
{
GroupItem groupItem = fe as GroupItem;
if (groupItem != null && groupItem.ItemsHost != null)
{
result = FindEndFocusableLeafContainer(groupItem.ItemsHost, last);
}
}
if (result != null)
{
return result;
}
else if (KeyboardNavigation.IsFocusableInternal(fe))
{
return fe;
}
}
i += incr;
}
}
return null;
}
internal void NavigateToItem(ItemInfo info, ItemNavigateArgs itemNavigateArgs, bool alwaysAtTopOfViewport=false)
{
if (info != null)
{
NavigateToItem(info.Item, info.Index, itemNavigateArgs, alwaysAtTopOfViewport);
}
}
internal void NavigateToItem(object item, ItemNavigateArgs itemNavigateArgs)
{
NavigateToItem(item, -1, itemNavigateArgs, false /* alwaysAtTopOfViewport */);
}
internal void NavigateToItem(object item, int itemIndex, ItemNavigateArgs itemNavigateArgs)
{
NavigateToItem(item, itemIndex, itemNavigateArgs, false /* alwaysAtTopOfViewport */);
}
internal void NavigateToItem(object item, ItemNavigateArgs itemNavigateArgs, bool alwaysAtTopOfViewport)
{
NavigateToItem(item, -1, itemNavigateArgs, alwaysAtTopOfViewport);
}
private void NavigateToItem(object item, int elementIndex, ItemNavigateArgs itemNavigateArgs, bool alwaysAtTopOfViewport)
{
// need to deal with more than 1-D no-wrapping virtualization
// Perhaps the container isn't generated yet. In this case we try to shift the view,
// wait for measure, and then call it again.
if (item == DependencyProperty.UnsetValue)
{
return;
}
if (elementIndex == -1)
{
elementIndex = Items.IndexOf(item);
if (elementIndex == -1)
return;
}
bool isHorizontal = false;
if (ItemsHost != null)
{
isHorizontal = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
}
FrameworkElement container;
FocusNavigationDirection direction = isHorizontal ? FocusNavigationDirection.Right : FocusNavigationDirection.Down;
MakeVisible(elementIndex, direction, alwaysAtTopOfViewport, out container);
FocusItem(NewItemInfo(item, container), itemNavigateArgs);
}
private object FindFocusable(int startIndex, int direction, out int foundIndex, out FrameworkElement foundContainer)
{
// HasItems may be wrong when underlying collection does not notify, but this function
// only cares about what's been generated and is consistent with ItemsControl state.
if (HasItems)
{
int count = Items.Count;
for (; startIndex >= 0 && startIndex < count; startIndex += direction)
{
FrameworkElement container = ItemContainerGenerator.ContainerFromIndex(startIndex) as FrameworkElement;
// If the UI is non-null it must meet some minimum requirements to consider it for
// navigation (focusable, enabled). If it has no UI we can make no judgements about it
// at this time, so it is navigable.
if (container == null || Keyboard.IsFocusable(container))
{
foundIndex = startIndex;
foundContainer = container;
return Items[startIndex];
}
}
}
foundIndex = -1;
foundContainer = null;
return null;
}
private void AdjustOffsetToAlignWithEdge(FrameworkElement element, FocusNavigationDirection direction)
{
Debug.Assert(ScrollHost != null, "This operation to adjust the offset along an edge is only possible when there is a ScrollHost available");
if (VirtualizingPanel.GetScrollUnit(this) != ScrollUnit.Item)
{
ScrollViewer scrollHost = ScrollHost;
FrameworkElement viewportElement = GetViewportElement();
element = TryGetTreeViewItemHeader(element) as FrameworkElement;
Rect elementBounds = new Rect(new Point(), element.RenderSize);
elementBounds = element.TransformToAncestor(viewportElement).TransformBounds(elementBounds);
bool isHorizontal = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
if (direction == FocusNavigationDirection.Down)
{
// Align with the bottom edge of viewport
if (isHorizontal)
{
scrollHost.ScrollToHorizontalOffset(scrollHost.HorizontalOffset - scrollHost.ViewportWidth + elementBounds.Right);
}
else
{
scrollHost.ScrollToVerticalOffset(scrollHost.VerticalOffset - scrollHost.ViewportHeight + elementBounds.Bottom);
}
}
else if (direction == FocusNavigationDirection.Up)
{
// Align with the top edge of viewport
if (isHorizontal)
{
scrollHost.ScrollToHorizontalOffset(scrollHost.HorizontalOffset + elementBounds.Left);
}
else
{
scrollHost.ScrollToVerticalOffset(scrollHost.VerticalOffset + elementBounds.Top);
}
}
}
}
//
// Shifts the viewport to make the given index visible.
//
private void MakeVisible(int index, FocusNavigationDirection direction, bool alwaysAtTopOfViewport, out FrameworkElement container)
{
container = null;
if (index >= 0)
{
container = ItemContainerGenerator.ContainerFromIndex(index) as FrameworkElement;
if (container == null)
{
// In case of VirtualizingPanel, the container might not have been
// generated yet. Hence try generating it.
VirtualizingPanel virtualizingPanel = ItemsHost as VirtualizingPanel;
if (virtualizingPanel != null)
{
virtualizingPanel.BringIndexIntoView(index);
UpdateLayout();
container = ItemContainerGenerator.ContainerFromIndex(index) as FrameworkElement;
}
}
MakeVisible(container, direction, alwaysAtTopOfViewport);
}
}
//
// Shifts the viewport to make the given item visible.
//
private void MakeVisible(ItemInfo info, FocusNavigationDirection direction, out FrameworkElement container)
{
if (info != null)
{
MakeVisible(info.Index, direction, false /*alwaysAtTopOfViewport*/, out container);
info.Container = container;
}
else
{
MakeVisible(-1, direction, false /*alwaysAtTopOfViewport*/, out container);
}
}
//
// Shifts the viewport to make the given index visible.
//
internal void MakeVisible(FrameworkElement container, FocusNavigationDirection direction, bool alwaysAtTopOfViewport)
{
if (ScrollHost != null && ItemsHost != null)
{
double oldHorizontalOffset;
double oldVerticalOffset;
FrameworkElement viewportElement = GetViewportElement();
while (container != null && !IsOnCurrentPage(viewportElement, container, direction, false /*fullyVisible*/))
{
oldHorizontalOffset = ScrollHost.HorizontalOffset;
oldVerticalOffset = ScrollHost.VerticalOffset;
container.BringIntoView();
// Wait for layout
ItemsHost.UpdateLayout();
// If offset does not change - exit the loop
if (DoubleUtil.AreClose(oldHorizontalOffset, ScrollHost.HorizontalOffset) &&
DoubleUtil.AreClose(oldVerticalOffset, ScrollHost.VerticalOffset))
break;
}
if (container != null && alwaysAtTopOfViewport)
{
bool isHorizontal = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
FrameworkElement firstElement;
GetFirstItemOnCurrentPage(container, FocusNavigationDirection.Up, out firstElement);
while (firstElement != container)
{
oldHorizontalOffset = ScrollHost.HorizontalOffset;
oldVerticalOffset = ScrollHost.VerticalOffset;
if (isHorizontal)
{
ScrollHost.LineRight();
}
else
{
ScrollHost.LineDown();
}
ScrollHost.UpdateLayout();
// If offset does not change - exit the loop
if (DoubleUtil.AreClose(oldHorizontalOffset, ScrollHost.HorizontalOffset) &&
DoubleUtil.AreClose(oldVerticalOffset, ScrollHost.VerticalOffset))
break;
GetFirstItemOnCurrentPage(container, FocusNavigationDirection.Up, out firstElement);
}
}
}
}
private bool NavigateToFirstItemOnCurrentPage(object startingItem, FocusNavigationDirection direction, ItemNavigateArgs itemNavigateArgs, bool shouldFocus, out FrameworkElement container)
{
object firstItem = GetFirstItemOnCurrentPage(ItemContainerGenerator.ContainerFromItem(startingItem) as FrameworkElement,
direction,
out container);
if (firstItem != DependencyProperty.UnsetValue)
{
if (shouldFocus)
{
return FocusItem(NewItemInfo(firstItem, container), itemNavigateArgs);
}
}
return false;
}
private object GetFirstItemOnCurrentPage(FrameworkElement startingElement,
FocusNavigationDirection direction,
out FrameworkElement firstElement)
{
Debug.Assert(direction == FocusNavigationDirection.Up || direction == FocusNavigationDirection.Down, "Can only get the first item on a page using North or South");
bool isHorizontal = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal);
bool isVertical = (ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Vertical);
if (ScrollHost != null &&
ScrollHost.CanContentScroll &&
VirtualizingPanel.GetScrollUnit(this) == ScrollUnit.Item &&
!(this is TreeView) &&
!IsGrouping)
{
int foundIndex = -1;
if (isVertical)
{
if (direction == FocusNavigationDirection.Up)
{
return FindFocusable((int)ScrollHost.VerticalOffset, 1, out foundIndex, out firstElement);
}
else
{
return FindFocusable((int)(ScrollHost.VerticalOffset + Math.Max(ScrollHost.ViewportHeight - 1, 0)),
-1,
out foundIndex,
out firstElement);
}
}
else if (isHorizontal)
{
if (direction == FocusNavigationDirection.Up)
{
return FindFocusable((int)ScrollHost.HorizontalOffset, 1, out foundIndex, out firstElement);
}
else
{
return FindFocusable((int)(ScrollHost.HorizontalOffset + Math.Max(ScrollHost.ViewportWidth - 1, 0)),
-1,
out foundIndex,
out firstElement);
}
}
}
//
// We assume we're physically scrolling in both directions now.
//
if (startingElement != null)
{
FrameworkElement currentElement = startingElement;
if (isHorizontal)
{
// In horizontal orientation left/right directions must used to
// predict the focus.
if (direction == FocusNavigationDirection.Up)
{
direction = FocusNavigationDirection.Left;
}
else if (direction == FocusNavigationDirection.Down)
{
direction = FocusNavigationDirection.Right;
}
}
FrameworkElement viewportElement = GetViewportElement();
bool treeViewNavigation = (this is TreeView);
currentElement = KeyboardNavigation.Current.PredictFocusedElementAtViewportEdge(startingElement,
direction,
treeViewNavigation,
viewportElement,
viewportElement) as FrameworkElement;
object returnItem = null;
firstElement = null;
if (currentElement != null)
{
returnItem = GetEncapsulatingItem(currentElement, out firstElement);
}
if (currentElement == null || returnItem == DependencyProperty.UnsetValue)
{
// Try the startingElement as a candidate.
ElementViewportPosition elementPosition = GetElementViewportPosition(viewportElement,
startingElement,
direction,
false /*fullyVisible*/);
if (elementPosition == ElementViewportPosition.CompletelyInViewport ||
elementPosition == ElementViewportPosition.PartiallyInViewport)
{
currentElement = startingElement;
returnItem = GetEncapsulatingItem(currentElement, out firstElement);
}
}
if (returnItem != null && returnItem is CollectionViewGroupInternal)
{
firstElement = currentElement;
}
return returnItem;
}
firstElement = null;
return null;
}
internal FrameworkElement GetViewportElement()
{
// NOTE: When ScrollHost is non-null, we use ScrollHost instead of
// ItemsHost because ItemsHost in the physically scrolling
// case will just have its layout offset shifted, and all
// items will always be within the bounding box of the ItemsHost,
// and we want to know if you can actually see the element.
FrameworkElement viewPort = ScrollHost;
if (viewPort == null)
{
viewPort = ItemsHost;
}
else
{
// Try use the ScrollContentPresenter as the viewport it is it available
// because that is more representative of the viewport in case of
// DataGrid when the ColumnHeaders need to be excluded from the
// dimensions of the viewport.
ScrollContentPresenter scp = viewPort.GetTemplateChild(ScrollViewer.ScrollContentPresenterTemplateName) as ScrollContentPresenter;
if (scp != null)
{
viewPort = scp;
}
}
return viewPort;
}
/// <summary>
/// Determines if the given item is on the current visible page.
/// </summary>
private bool IsOnCurrentPage(object item, FocusNavigationDirection axis)
{
FrameworkElement container = ItemContainerGenerator.ContainerFromItem(item) as FrameworkElement;
if (container == null)
{
return false;
}
return (GetElementViewportPosition(GetViewportElement(), container, axis, false) == ElementViewportPosition.CompletelyInViewport);
}
private bool IsOnCurrentPage(FrameworkElement element, FocusNavigationDirection axis)
{
return (GetElementViewportPosition(GetViewportElement(), element, axis, false) == ElementViewportPosition.CompletelyInViewport);
}
/// <summary>
/// Determines if the given element is on the current visible page.
/// The element must be completely on the page on the given axis, but need
/// not be completely contained on the page in the perpendicular axis.
/// For example, if axis == North, then the element's Top and Bottom must
/// be completely contained on the page.
/// </summary>
private bool IsOnCurrentPage(FrameworkElement viewPort, FrameworkElement element, FocusNavigationDirection axis, bool fullyVisible)
{
return (GetElementViewportPosition(viewPort, element, axis, fullyVisible) == ElementViewportPosition.CompletelyInViewport);
}
internal static ElementViewportPosition GetElementViewportPosition(FrameworkElement viewPort,
UIElement element,
FocusNavigationDirection axis,
bool fullyVisible)
{
Rect elementRect;
return GetElementViewportPosition(viewPort, element, axis, fullyVisible, out elementRect);
}
internal static ElementViewportPosition GetElementViewportPosition(FrameworkElement viewPort,
UIElement element,
FocusNavigationDirection axis,
bool fullyVisible,
out Rect elementRect)
{
return GetElementViewportPosition(
viewPort,
element,
axis,
fullyVisible,
false,
out elementRect);
}
/// <summary>
/// Determines if the given element is
/// 1) Completely in the current visible page along the given axis.
/// 2) Partially in the current visible page.
/// 3) Before the current page along the given axis.
/// 4) After the current page along the given axis.
/// fullyVisible parameter specifies if the element needs to be completely
/// in the current visible page along the perpendicular axis (if it is
/// completely in the page along the major axis).
/// ignorePerpendicularAxis parameter specifies whether the position of
/// given element along the secondary axis doesn't matter
/// </summary>
internal static ElementViewportPosition GetElementViewportPosition(FrameworkElement viewPort,
UIElement element,
FocusNavigationDirection axis,
bool fullyVisible,
bool ignorePerpendicularAxis,
out Rect elementRect)
{
elementRect = Rect.Empty;
// If there's no ScrollHost or ItemsHost, the element is not on the page
if (viewPort == null)
{
return ElementViewportPosition.None;
}
if (element == null || !viewPort.IsAncestorOf(element))
{
return ElementViewportPosition.None;
}
Rect viewPortBounds = new Rect(new Point(), viewPort.RenderSize);
Rect elementBounds = new Rect(new Point(), element.RenderSize);
elementBounds = CorrectCatastrophicCancellation(element.TransformToAncestor(viewPort)).TransformBounds(elementBounds);
bool northSouth = (axis == FocusNavigationDirection.Up || axis == FocusNavigationDirection.Down);
bool eastWest = (axis == FocusNavigationDirection.Left || axis == FocusNavigationDirection.Right);
elementRect = elementBounds;
if (ignorePerpendicularAxis)
{
// expand the viewport bounds to infinity along the secondary axis
if (northSouth)
{
viewPortBounds = new Rect(Double.NegativeInfinity, viewPortBounds.Top,
Double.PositiveInfinity, viewPortBounds.Height);
}
else if (eastWest)
{
viewPortBounds = new Rect(viewPortBounds.Left, Double.NegativeInfinity,
viewPortBounds.Width, Double.PositiveInfinity);
}
}
// Return true if the element is completely contained within the page along the given axis.
if (fullyVisible)
{
if (viewPortBounds.Contains(elementBounds))
{
return ElementViewportPosition.CompletelyInViewport;
}
}
else
{
if (northSouth)
{
if (DoubleUtil.LessThanOrClose(viewPortBounds.Top, elementBounds.Top)
&& DoubleUtil.LessThanOrClose(elementBounds.Bottom, viewPortBounds.Bottom))
{
return ElementViewportPosition.CompletelyInViewport;
}
}
else if (eastWest)
{
if (DoubleUtil.LessThanOrClose(viewPortBounds.Left, elementBounds.Left)
&& DoubleUtil.LessThanOrClose(elementBounds.Right, viewPortBounds.Right))
{
return ElementViewportPosition.CompletelyInViewport;
}
}
}
if (ElementIntersectsViewport(viewPortBounds, elementBounds))
{
return ElementViewportPosition.PartiallyInViewport;
}
else if ((northSouth && DoubleUtil.LessThanOrClose(elementBounds.Bottom, viewPortBounds.Top)) ||
(eastWest && DoubleUtil.LessThanOrClose(elementBounds.Right, viewPortBounds.Left)))
{
return ElementViewportPosition.BeforeViewport;
}
else if ((northSouth && DoubleUtil.LessThanOrClose(viewPortBounds.Bottom, elementBounds.Top)) ||
(eastWest && DoubleUtil.LessThanOrClose(viewPortBounds.Right, elementBounds.Left)))
{
return ElementViewportPosition.AfterViewport;
}
return ElementViewportPosition.None;
}
// this version also returns the element's layout rectangle (in viewport's coordinates).
// VirtualizingStackPanel needs this, to determine the element's scroll offset.
internal static ElementViewportPosition GetElementViewportPosition(FrameworkElement viewPort,
UIElement element,
FocusNavigationDirection axis,
bool fullyVisible,
bool ignorePerpendicularAxis,
out Rect elementRect,
out Rect layoutRect)
{
ElementViewportPosition position = GetElementViewportPosition(
viewPort,
element,
axis,
fullyVisible,
false,
out elementRect);
if (position == ElementViewportPosition.None)
{
layoutRect = Rect.Empty;
}
else
{
Visual parent = VisualTreeHelper.GetParent(element) as Visual;
Debug.Assert(element != viewPort && element.IsArrangeValid && parent != null, "GetElementViewportPosition called in unsupported situation");
layoutRect = CorrectCatastrophicCancellation(parent.TransformToAncestor(viewPort)).TransformBounds(element.PreviousArrangeRect);
}
return position;
}
// in large virtualized hierarchical lists (TreeView or grouping), the transform
// returned by element.TransformToAncestor(viewport) is vulnerable to catastrophic
// cancellation. If element is at the top of the viewport, but embedded in
// layers of the hierarchy, the contributions of the intermediate elements add
// up to a large positive number which should exactly cancel out the large
// negative offset of the viewport's direct child to produce net offset of 0.0.
// But floating-point drift while accumulating the intermediate offsets and
// catastrophic cancellation in the last step may produce a very small
// non-zero number instead (e.g. -0.0000000000006548). This can lead to
// infinite loops and incorrect decisions in layout.
// To mitigate this problem, replace near-zero offsets with zero.
private static GeneralTransform CorrectCatastrophicCancellation(GeneralTransform transform)
{
MatrixTransform matrixTransform = transform as MatrixTransform;
if (matrixTransform != null)
{
bool needNewTransform = false;
Matrix matrix = matrixTransform.Matrix;
if (matrix.OffsetX != 0.0 && LayoutDoubleUtil.AreClose(matrix.OffsetX, 0.0))
{
matrix.OffsetX = 0.0;
needNewTransform = true;
}
if (matrix.OffsetY != 0.0 && LayoutDoubleUtil.AreClose(matrix.OffsetY, 0.0))
{
matrix.OffsetY = 0.0;
needNewTransform = true;
}
if (needNewTransform)
{
transform = new MatrixTransform(matrix);
}
}
return transform;
}
private static bool ElementIntersectsViewport(Rect viewportRect, Rect elementRect)
{
if (viewportRect.IsEmpty || elementRect.IsEmpty)
{
return false;
}
if (DoubleUtil.LessThan(elementRect.Right, viewportRect.Left) || LayoutDoubleUtil.AreClose(elementRect.Right, viewportRect.Left) ||
DoubleUtil.GreaterThan(elementRect.Left, viewportRect.Right) || LayoutDoubleUtil.AreClose(elementRect.Left, viewportRect.Right) ||
DoubleUtil.LessThan(elementRect.Bottom, viewportRect.Top) || LayoutDoubleUtil.AreClose(elementRect.Bottom, viewportRect.Top) ||
DoubleUtil.GreaterThan(elementRect.Top, viewportRect.Bottom) || LayoutDoubleUtil.AreClose(elementRect.Top, viewportRect.Bottom))
{
return false;
}
return true;
}
private bool IsInDirectionForLineNavigation(Rect fromRect, Rect toRect, FocusNavigationDirection direction, bool isHorizontal)
{
Debug.Assert(direction == FocusNavigationDirection.Up ||
direction == FocusNavigationDirection.Down);
if (direction == FocusNavigationDirection.Down)
{
if (isHorizontal)
{
// Right
return DoubleUtil.GreaterThanOrClose(toRect.Left, fromRect.Left);
}
else
{
// Down
return DoubleUtil.GreaterThanOrClose(toRect.Top, fromRect.Top);
}
}
else if (direction == FocusNavigationDirection.Up)
{
if (isHorizontal)
{
// Left
return DoubleUtil.LessThanOrClose(toRect.Right, fromRect.Right);
}
else
{
// UP
return DoubleUtil.LessThanOrClose(toRect.Bottom, fromRect.Bottom);
}
}
return false;
}
private static void OnGotFocus(object sender, KeyboardFocusChangedEventArgs e)
{
ItemsControl itemsControl = (ItemsControl)sender;
UIElement focusedElement = e.OriginalSource as UIElement;
if ((focusedElement != null) && (focusedElement != itemsControl))
{
object item = itemsControl.ItemContainerGenerator.ItemFromContainer(focusedElement);
if (item != DependencyProperty.UnsetValue)
{
itemsControl._focusedInfo = itemsControl.NewItemInfo(item, focusedElement);
}
else if (itemsControl._focusedInfo != null)
{
UIElement itemContainer = itemsControl._focusedInfo.Container as UIElement;
if (itemContainer == null ||
!Helper.IsAnyAncestorOf(itemContainer, focusedElement))
{
itemsControl._focusedInfo = null;
}
}
}
}
/// <summary>
/// The item corresponding to the UI container which has focus.
/// Virtualizing panels remove visual children you can't see.
/// When you scroll the focused element out of view we throw
/// focus back on to the items control and remember the item which
/// was focused. When it scrolls back into view (and focus is
/// still on the ItemsControl) we'll focus it.
/// </summary>
internal ItemInfo FocusedInfo
{
get { return _focusedInfo; }
}
private ItemInfo _focusedInfo;
internal class ItemNavigateArgs
{
public ItemNavigateArgs(InputDevice deviceUsed, ModifierKeys modifierKeys)
{
_deviceUsed = deviceUsed;
_modifierKeys = modifierKeys;
}
public InputDevice DeviceUsed { get { return _deviceUsed; } }
private InputDevice _deviceUsed;
private ModifierKeys _modifierKeys;
public static ItemNavigateArgs Empty
{
get
{
if (_empty == null)
{
_empty = new ItemNavigateArgs(null, ModifierKeys.None);;
}
return _empty;
}
}
private static ItemNavigateArgs _empty;
}
// make this protected
internal virtual bool FocusItem(ItemInfo info, ItemNavigateArgs itemNavigateArgs)
{
object item = info.Item;
bool returnValue = false;
if (item != null)
{
UIElement container = info.Container as UIElement;
if (container != null)
{
returnValue = container.Focus();
}
}
if (itemNavigateArgs.DeviceUsed is KeyboardDevice)
{
KeyboardNavigation.ShowFocusVisual();
}
return returnValue;
}
// ISSUE: IsLogicalVertical and IsLogicalHorizontal are rough guesses as to whether
// the ItemsHost is virtualizing in a particular direction. Ideally this
// would be exposed through the IScrollInfo.
internal bool IsLogicalVertical
{
get
{
return (ItemsHost != null && ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Vertical &&
ScrollHost != null && ScrollHost.CanContentScroll &&
VirtualizingStackPanel.GetScrollUnit(this) == ScrollUnit.Item);
}
}
internal bool IsLogicalHorizontal
{
get
{
return (ItemsHost != null && ItemsHost.HasLogicalOrientation && ItemsHost.LogicalOrientation == Orientation.Horizontal &&
ScrollHost != null && ScrollHost.CanContentScroll &&
VirtualizingStackPanel.GetScrollUnit(this) == ScrollUnit.Item);
}
}
internal ScrollViewer ScrollHost
{
get
{
if (!ReadControlFlag(ControlBoolFlags.ScrollHostValid))
{
if (_itemsHost == null)
{
return null;
}
else
{
// We have an itemshost, so walk up the tree looking for the ScrollViewer
for (DependencyObject current = _itemsHost; current != this && current != null; current = VisualTreeHelper.GetParent(current))
{
ScrollViewer scrollViewer = current as ScrollViewer;
if (scrollViewer != null)
{
_scrollHost = scrollViewer;
break;
}
}
WriteControlFlag(ControlBoolFlags.ScrollHostValid, true);
}
}
return _scrollHost;
}
}
internal static TimeSpan AutoScrollTimeout
{
get
{
// NOTE: NtUser does the following (file: windows/ntuser/kernel/sysmet.c)
// gpsi->dtLBSearch = dtTime * 4; // dtLBSearch = 4 * gdtDblClk
// gpsi->dtScroll = gpsi->dtLBSearch / 5; // dtScroll = 4/5 * gdtDblClk
return TimeSpan.FromMilliseconds(MS.Win32.SafeNativeMethods.GetDoubleClickTime() * 0.8);
}
}
internal void DoAutoScroll()
{
DoAutoScroll(FocusedInfo);
}
internal void DoAutoScroll(ItemInfo startingInfo)
{
// Attempt to compute positions based on the ScrollHost.
// If that doesn't exist, use the ItemsHost.
FrameworkElement relativeTo = ScrollHost != null ? (FrameworkElement)ScrollHost : ItemsHost;
if (relativeTo != null)
{
// Figure out where the mouse is w.r.t. the ItemsControl.
Point mousePosition = Mouse.GetPosition(relativeTo);
// Take the bounding box of the ListBox and scroll against that
Rect bounds = new Rect(new Point(), relativeTo.RenderSize);
bool focusChanged = false;
if (mousePosition.Y < bounds.Top)
{
NavigateByLine(startingInfo, FocusNavigationDirection.Up, new ItemNavigateArgs(Mouse.PrimaryDevice, Keyboard.Modifiers));
focusChanged = startingInfo != FocusedInfo;
}
else if (mousePosition.Y >= bounds.Bottom)
{
NavigateByLine(startingInfo, FocusNavigationDirection.Down, new ItemNavigateArgs(Mouse.PrimaryDevice, Keyboard.Modifiers));
focusChanged = startingInfo != FocusedInfo;
}
// Try horizontal scroll if vertical scroll did not happen
if (!focusChanged)
{
if (mousePosition.X < bounds.Left)
{
FocusNavigationDirection direction = FocusNavigationDirection.Left;
if (IsRTL(relativeTo))
{
direction = FocusNavigationDirection.Right;
}
NavigateByLine(startingInfo, direction, new ItemNavigateArgs(Mouse.PrimaryDevice, Keyboard.Modifiers));
}
else if (mousePosition.X >= bounds.Right)
{
FocusNavigationDirection direction = FocusNavigationDirection.Right;
if (IsRTL(relativeTo))
{
direction = FocusNavigationDirection.Left;
}
NavigateByLine(startingInfo, direction, new ItemNavigateArgs(Mouse.PrimaryDevice, Keyboard.Modifiers));
}
}
}
}
private bool IsRTL(FrameworkElement element)
{
FlowDirection flowDirection = element.FlowDirection;
return (flowDirection == FlowDirection.RightToLeft);
}
private static ItemsControl GetEncapsulatingItemsControl(FrameworkElement element)
{
while (element != null)
{
ItemsControl itemsControl = ItemsControl.ItemsControlFromItemContainer(element);
if (itemsControl != null)
{
return itemsControl;
}
element = VisualTreeHelper.GetParent(element) as FrameworkElement;
}
return null;
}
private static object GetEncapsulatingItem(FrameworkElement element, out FrameworkElement container)
{
ItemsControl itemsControl = null;
return GetEncapsulatingItem(element, out container, out itemsControl);
}
private static object GetEncapsulatingItem(FrameworkElement element, out FrameworkElement container, out ItemsControl itemsControl)
{
object item = DependencyProperty.UnsetValue;
itemsControl = null;
while (element != null)
{
itemsControl = ItemsControl.ItemsControlFromItemContainer(element);
if (itemsControl != null)
{
item = itemsControl.ItemContainerGenerator.ItemFromContainer(element);
if (item != DependencyProperty.UnsetValue)
{
break;
}
}
element = VisualTreeHelper.GetParent(element) as FrameworkElement;
}
container = element;
return item;
}
internal static DependencyObject TryGetTreeViewItemHeader(DependencyObject element)
{
TreeViewItem treeViewItem = element as TreeViewItem;
if (treeViewItem != null)
{
return treeViewItem.TryGetHeaderElement();
}
return element;
}
#endregion Keyboard Navigation
#endregion
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
#region Private Methods
private void ApplyItemContainerStyle(DependencyObject container, object item)
{
FrameworkObject foContainer = new FrameworkObject(container);
// don't overwrite a locally-defined style (bug 1018408)
if (!foContainer.IsStyleSetFromGenerator &&
container.ReadLocalValue(FrameworkElement.StyleProperty) != DependencyProperty.UnsetValue)
{
return;
}
// Control's ItemContainerStyle has first stab
Style style = ItemContainerStyle;
// no ItemContainerStyle set, try ItemContainerStyleSelector
if (style == null)
{
if (ItemContainerStyleSelector != null)
{
style = ItemContainerStyleSelector.SelectStyle(item, container);
}
}
// apply the style, if found
if (style != null)
{
// verify style is appropriate before applying it
if (!style.TargetType.IsInstanceOfType(container))
throw new InvalidOperationException(SR.Format(SR.StyleForWrongType, style.TargetType.Name, container.GetType().Name));
foContainer.Style = style;
foContainer.IsStyleSetFromGenerator = true;
}
else if (foContainer.IsStyleSetFromGenerator)
{
// if Style was formerly set from ItemContainerStyle, clear it
foContainer.IsStyleSetFromGenerator = false;
container.ClearValue(FrameworkElement.StyleProperty);
}
}
private void RemoveItemContainerStyle(DependencyObject container)
{
FrameworkObject foContainer = new FrameworkObject(container);
if (foContainer.IsStyleSetFromGenerator)
{
container.ClearValue(FrameworkElement.StyleProperty);
}
}
internal object GetItemOrContainerFromContainer(DependencyObject container)
{
object item = ItemContainerGenerator.ItemFromContainer(container);
if (item == DependencyProperty.UnsetValue
&& ItemsControlFromItemContainer(container) == this
&& ((IGeneratorHost)this).IsItemItsOwnContainer(container))
{
item = container;
}
return item;
}
// A version of Object.Equals with paranoia for mismatched types, to avoid problems
// with classes that implement Object.Equals poorly
internal static bool EqualsEx(object o1, object o2)
{
try
{
return Object.Equals(o1, o2);
}
catch (System.InvalidCastException)
{
// A common programming error: the type of o1 overrides Equals(object o2)
// but mistakenly assumes that o2 has the same type as o1:
// MyType x = (MyType)o2;
// This throws InvalidCastException when o2 is a sentinel object,
// e.g. UnsetValue, DisconnectedItem, NewItemPlaceholder, etc.
// Rather than crash, just return false - the objects are clearly unequal.
return false;
}
}
#endregion
#region ItemInfo
// create an ItemInfo with as much information as can be deduced
internal ItemInfo NewItemInfo(object item, DependencyObject container=null, int index=-1)
{
return new ItemInfo(item, container, index).Refresh(ItemContainerGenerator);
}
// create an ItemInfo for the given container
internal ItemInfo ItemInfoFromContainer(DependencyObject container)
{
return NewItemInfo(ItemContainerGenerator.ItemFromContainer(container), container, ItemContainerGenerator.IndexFromContainer(container));
}
// create an ItemInfo for the given index
internal ItemInfo ItemInfoFromIndex(int index)
{
return (index >= 0) ? NewItemInfo(Items[index], ItemContainerGenerator.ContainerFromIndex(index), index)
: null;
}
// create an unresolved ItemInfo
internal ItemInfo NewUnresolvedItemInfo(object item)
{
return new ItemInfo(item, ItemInfo.UnresolvedContainer, -1);
}
// return the container corresponding to an ItemInfo
internal DependencyObject ContainerFromItemInfo(ItemInfo info)
{
DependencyObject container = info.Container;
if (container == null)
{
if (info.Index >= 0)
{
container = ItemContainerGenerator.ContainerFromIndex(info.Index);
info.Container = container;
}
else
{
container = ItemContainerGenerator.ContainerFromItem(info.Item);
// don't change info.Container - info is potentially shared by different ItemsControls
}
}
return container;
}
// adjust ItemInfos after a generator status change
internal void AdjustItemInfoAfterGeneratorChange(ItemInfo info)
{
if (info != null)
{
ItemInfo[] a = new ItemInfo[]{info};
AdjustItemInfosAfterGeneratorChange(a, claimUniqueContainer:false);
}
}
// adjust ItemInfos after a generator status change
internal void AdjustItemInfosAfterGeneratorChange(IEnumerable<ItemInfo> list, bool claimUniqueContainer)
{
// detect discarded containers and mark the ItemInfo accordingly
// (also see if there are infos awaiting containers)
bool resolvePendingContainers = false;
foreach (ItemInfo info in list)
{
DependencyObject container = info.Container;
if (container == null)
{
resolvePendingContainers = true;
}
else if (info.IsRemoved || !ItemsControl.EqualsEx(info.Item,
container.ReadLocalValue(ItemContainerGenerator.ItemForItemContainerProperty)))
{
info.Container = null;
resolvePendingContainers = true;
}
}
// if any of the ItemInfos correspond to containers
// that are now realized, record the container in the ItemInfo
if (resolvePendingContainers)
{
// first find containers that are already claimed by the list
List<DependencyObject> claimedContainers = new List<DependencyObject>();
if (claimUniqueContainer)
{
foreach (ItemInfo info in list)
{
DependencyObject container = info.Container;
if (container != null)
{
claimedContainers.Add(container);
}
}
}
// now try to match the pending items with an unclaimed container
foreach (ItemInfo info in list)
{
DependencyObject container = info.Container;
if (container == null)
{
int index = info.Index;
if (index >= 0)
{
// if we know the index, see if the container exists
container = ItemContainerGenerator.ContainerFromIndex(index);
}
else
{
// otherwise see if an unclaimed container matches the item
object item = info.Item;
ItemContainerGenerator.FindItem(
static (state, o, d) => ItemsControl.EqualsEx(o, state.item) && !state.claimedContainers.Contains(d),
(item, claimedContainers),
out container, out index);
}
if (container != null)
{
// update ItemInfo and claim the container
info.Container = container;
info.Index = index;
if (claimUniqueContainer)
{
claimedContainers.Add(container);
}
}
}
}
}
}
// correct the indices in the given ItemInfo, in response to a collection change event
internal void AdjustItemInfo(NotifyCollectionChangedEventArgs e, ItemInfo info)
{
if (info != null)
{
ItemInfo[] a = new ItemInfo[]{info};
AdjustItemInfos(e, a);
}
}
// correct the indices in the given ItemInfos, in response to a collection change event
internal void AdjustItemInfos(NotifyCollectionChangedEventArgs e, IEnumerable<ItemInfo> list)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
// items at NewStartingIndex and above have moved up 1
foreach (ItemInfo info in list)
{
int index = info.Index;
if (index >= e.NewStartingIndex)
{
info.Index = index + 1;
}
}
break;
case NotifyCollectionChangedAction.Remove:
// items at OldStartingIndex and above have moved down 1
foreach (ItemInfo info in list)
{
int index = info.Index;
if (index > e.OldStartingIndex)
{
info.Index = index - 1;
}
else if (index == e.OldStartingIndex)
{
info.Index = -1;
}
}
break;
case NotifyCollectionChangedAction.Move:
// items between New and Old have moved. The direction and
// exact endpoints depends on whether New comes before Old.
int left, right, delta;
if (e.OldStartingIndex < e.NewStartingIndex)
{
left = e.OldStartingIndex + 1;
right = e.NewStartingIndex;
delta = -1;
}
else
{
left = e.NewStartingIndex;
right = e.OldStartingIndex - 1;
delta = 1;
}
foreach (ItemInfo info in list)
{
int index = info.Index;
if (index == e.OldStartingIndex)
{
info.Index = e.NewStartingIndex;
}
else if (left <= index && index <= right)
{
info.Index = index + delta;
}
}
break;
case NotifyCollectionChangedAction.Replace:
// nothing to do
break;
case NotifyCollectionChangedAction.Reset:
// the indices and containers are no longer valid
foreach (ItemInfo info in list)
{
info.Index = -1;
info.Container = null;
}
break;
}
}
// return an ItemInfo like the input one, but owned by this ItemsControl
internal ItemInfo LeaseItemInfo(ItemInfo info, bool ensureIndex=false)
{
// if the original has index data, it's already good enough
if (info.Index < 0)
{
// otherwise create a new info from the original's item
info = NewItemInfo(info.Item);
if (ensureIndex && info.Index < 0)
{
info.Index = Items.IndexOf(info.Item);
}
}
return info;
}
// refresh an ItemInfo
internal void RefreshItemInfo(ItemInfo info)
{
if (info != null)
{
info.Refresh(ItemContainerGenerator);
}
}
[DebuggerDisplay("Index: {Index} Item: {Item}")]
internal class ItemInfo
{
internal object Item { get; private set; }
internal DependencyObject Container { get; set; }
internal int Index { get; set; }
internal static readonly DependencyObject SentinelContainer = new DependencyObject();
internal static readonly DependencyObject UnresolvedContainer = new DependencyObject();
internal static readonly DependencyObject KeyContainer = new DependencyObject();
internal static readonly DependencyObject RemovedContainer = new DependencyObject();
static ItemInfo()
{
// mark the special DOs as sentinels. This helps catch bugs involving
// using them accidentally for anything besides equality comparison.
SentinelContainer.MakeSentinel();
UnresolvedContainer.MakeSentinel();
KeyContainer.MakeSentinel();
RemovedContainer.MakeSentinel();
}
public ItemInfo(object item, DependencyObject container=null, int index=-1)
{
Item = item;
Container = container;
Index = index;
}
internal bool IsResolved { get { return Container != UnresolvedContainer; } }
internal bool IsKey { get { return Container == KeyContainer; } }
internal bool IsRemoved { get { return Container == RemovedContainer; } }
internal ItemInfo Clone()
{
return new ItemInfo(Item, Container, Index);
}
internal static ItemInfo Key(ItemInfo info)
{
return (info.Container == UnresolvedContainer)
? new ItemInfo(info.Item, KeyContainer, -1)
: info;
}
public override int GetHashCode()
{
return (Item != null) ? Item.GetHashCode() : 314159;
}
public override bool Equals(object o)
{
if (o == (object)this)
return true;
ItemInfo that = o as ItemInfo;
if (that == null)
return false;
return Equals(that, matchUnresolved:false);
}
internal bool Equals(ItemInfo that, bool matchUnresolved)
{
// Removed matches nothing
if (this.IsRemoved || that.IsRemoved)
return false;
// items must match
if (!ItemsControl.EqualsEx(this.Item, that.Item))
return false;
// Key matches anything, except Unresolved when matchUnresovled is false
if (this.Container == KeyContainer)
return matchUnresolved || that.Container != UnresolvedContainer;
else if (that.Container == KeyContainer)
return matchUnresolved || this.Container != UnresolvedContainer;
// Unresolved matches nothing
if (this.Container == UnresolvedContainer || that.Container == UnresolvedContainer)
return false;
return
(this.Container == that.Container)
? (this.Container == SentinelContainer)
? (this.Index == that.Index) // Sentinel => negative indices are significant
: (this.Index < 0 || that.Index < 0 ||
this.Index == that.Index) // ~Sentinel => ignore negative indices
: (this.Container == SentinelContainer) || // sentinel matches non-sentinel
(that.Container == SentinelContainer) ||
( (this.Container == null || that.Container == null) && // null matches non-null
(this.Index < 0 || that.Index < 0 || // provided that indices match
this.Index == that.Index));
}
public static bool operator ==(ItemInfo info1, ItemInfo info2)
{
return Object.Equals(info1, info2);
}
public static bool operator !=(ItemInfo info1, ItemInfo info2)
{
return !Object.Equals(info1, info2);
}
// update container and index with current values
internal ItemInfo Refresh(ItemContainerGenerator generator)
{
if (Container == null && Index < 0)
{
Container = generator.ContainerFromItem(Item);
}
if (Index < 0 && Container != null)
{
Index = generator.IndexFromContainer(Container);
}
if (Container == null && Index >= 0)
{
Container = generator.ContainerFromIndex(Index);
}
if (Container == SentinelContainer && Index >= 0)
{
Container = null; // caller explicitly wants null container
}
return this;
}
// Don't call this on entries used in hashtables - it changes the hashcode
internal void Reset(object item)
{
Item = item;
}
}
#endregion ItemInfo
#region ItemValueStorage
object IContainItemStorage.ReadItemValue(object item, DependencyProperty dp)
{
return Helper.ReadItemValue(this, item, dp.GlobalIndex);
}
void IContainItemStorage.StoreItemValue(object item, DependencyProperty dp, object value)
{
Helper.StoreItemValue(this, item, dp.GlobalIndex, value);
}
void IContainItemStorage.ClearItemValue(object item, DependencyProperty dp)
{
Helper.ClearItemValue(this, item, dp.GlobalIndex);
}
void IContainItemStorage.ClearValue(DependencyProperty dp)
{
Helper.ClearItemValueStorage(this, new int[] {dp.GlobalIndex});
}
void IContainItemStorage.Clear()
{
Helper.ClearItemValueStorage(this);
}
#endregion
#region Method Overrides
/// <summary>
/// Returns a string representation of this object.
/// </summary>
/// <returns></returns>
public override string ToString()
{
// HasItems may be wrong when underlying collection does not notify,
// but this function should try to return what's consistent with ItemsControl state.
int itemsCount = HasItems ? Items.Count : 0;
return SR.Format(SR.ToStringFormatString_ItemsControl, this.GetType(), itemsCount);
}
protected override AutomationPeer OnCreateAutomationPeer()
{
if (!AccessibilitySwitches.ItemsControlDoesNotSupportAutomation)
{
return new ItemsControlWrapperAutomationPeer(this);
}
return null;
}
// This should really override OnCreateAutomationPeer, but that API addition
// isn't an option. When it becomes an option:
// a. rename this method to OnCreateAutomationPeer
// b. change its visibilty from internal to protected
// c. remove UIElement.OnCreateAutomationPeerInternal, and its use in
// UIElement.CreateAutomationPeer
// d. change visibility of ItemsControlWrapperAutomationPeer and
// ItemsControlItemAutomationPeer from internal to public
internal override AutomationPeer OnCreateAutomationPeerInternal()
{
return new ItemsControlWrapperAutomationPeer(this);
}
#endregion
#region Data
private ItemCollection _items; // Cache for Items property
private ItemContainerGenerator _itemContainerGenerator;
private Panel _itemsHost;
private ScrollViewer _scrollHost;
private ObservableCollection<GroupStyle> _groupStyle = new ObservableCollection<GroupStyle>();
private static readonly UncommonField<bool> ShouldCoerceScrollUnitField = new UncommonField<bool>();
private static readonly UncommonField<bool> ShouldCoerceCacheSizeField = new UncommonField<bool>();
#endregion
#region DTypeThemeStyleKey
// Returns the DependencyObjectType for the registered ThemeStyleKey's default
// value. Controls will override this method to return approriate types.
internal override DependencyObjectType DTypeThemeStyleKey
{
get { return _dType; }
}
private static DependencyObjectType _dType;
#endregion DTypeThemeStyleKey
}
internal enum ElementViewportPosition
{
None,
BeforeViewport,
PartiallyInViewport,
CompletelyInViewport,
AfterViewport
}
}
|