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// 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.Diagnostics;
using MS.Internal;
using MS.Internal.KnownBoxes;
using MS.Utility;
using System.Windows.Threading;
using System.ComponentModel;
using System.Windows.Automation;
using System.Windows.Automation.Peers;
using System.Windows.Media;
using System.Windows.Input;
using System.Windows;
using System.Windows.Data;
using System.Windows.Controls.Primitives;
// Disable CS3001: Warning as Error: not CLS-compliant
#pragma warning disable 3001
namespace System.Windows.Controls
{
/// <summary>
/// A child item of TabControl.
/// </summary>
[DefaultEvent("IsSelectedChanged")]
public class TabItem : HeaderedContentControl
{
//-------------------------------------------------------------------
//
// Constructors
//
//-------------------------------------------------------------------
#region Constructors
/// <summary>
/// Default DependencyObject constructor
/// </summary>
/// <remarks>
/// Automatic determination of current Dispatcher. Use alternative constructor
/// that accepts a Dispatcher for best performance.
/// </remarks>
public TabItem() : base()
{
}
static TabItem()
{
EventManager.RegisterClassHandler(typeof(TabItem), AccessKeyManager.AccessKeyPressedEvent, new AccessKeyPressedEventHandler(OnAccessKeyPressed));
DefaultStyleKeyProperty.OverrideMetadata(typeof(TabItem), new FrameworkPropertyMetadata(typeof(TabItem)));
_dType = DependencyObjectType.FromSystemTypeInternal(typeof(TabItem));
KeyboardNavigation.DirectionalNavigationProperty.OverrideMetadata(typeof(TabItem), new FrameworkPropertyMetadata(KeyboardNavigationMode.Contained));
KeyboardNavigation.TabNavigationProperty.OverrideMetadata(typeof(TabItem), new FrameworkPropertyMetadata(KeyboardNavigationMode.Local));
IsEnabledProperty.OverrideMetadata(typeof(TabItem), new UIPropertyMetadata(new PropertyChangedCallback(OnVisualStatePropertyChanged)));
IsMouseOverPropertyKey.OverrideMetadata(typeof(TabItem), new UIPropertyMetadata(new PropertyChangedCallback(OnVisualStatePropertyChanged)));
AutomationProperties.IsOffscreenBehaviorProperty.OverrideMetadata(typeof(TabItem), new FrameworkPropertyMetadata(IsOffscreenBehavior.FromClip));
}
#endregion
//-------------------------------------------------------------------
//
// Properties
//
//-------------------------------------------------------------------
#region Properties
/// <summary>
/// Indicates whether this TabItem is selected.
/// </summary>
public static readonly DependencyProperty IsSelectedProperty =
Selector.IsSelectedProperty.AddOwner(typeof(TabItem),
new FrameworkPropertyMetadata(BooleanBoxes.FalseBox,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault | FrameworkPropertyMetadataOptions.AffectsParentMeasure | FrameworkPropertyMetadataOptions.Journal,
new PropertyChangedCallback(OnIsSelectedChanged)));
/// <summary>
/// Indicates whether this TabItem is selected.
/// </summary>
[Bindable(true), Category("Appearance")]
public bool IsSelected
{
get { return (bool) GetValue(IsSelectedProperty); }
set { SetValue(IsSelectedProperty, BooleanBoxes.Box(value)); }
}
private static void OnIsSelectedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
TabItem tabItem = d as TabItem;
bool isSelected = (bool)e.NewValue;
TabControl parentTabControl = tabItem.TabControlParent;
if (parentTabControl != null)
{
parentTabControl.RaiseIsSelectedChangedAutomationEvent(tabItem, isSelected);
}
if (isSelected)
{
tabItem.OnSelected(new RoutedEventArgs(Selector.SelectedEvent, tabItem));
}
else
{
tabItem.OnUnselected(new RoutedEventArgs(Selector.UnselectedEvent, tabItem));
}
// KeyboardNavigation use bounding box reduced with DirectionalNavigationMargin when calculating the next element in directional navigation
// Because TabItem use negative margins some TabItems overlap which would changes the directional navigation if we don't reduce the bounding box
if (isSelected)
{
Binding binding = new Binding("Margin");
binding.Source = tabItem;
BindingOperations.SetBinding(tabItem, KeyboardNavigation.DirectionalNavigationMarginProperty, binding);
}
else
{
BindingOperations.ClearBinding(tabItem, KeyboardNavigation.DirectionalNavigationMarginProperty);
}
tabItem.UpdateVisualState();
}
/// <summary>
/// Event indicating that the IsSelected property is now true.
/// </summary>
/// <param name="e">Event arguments</param>
protected virtual void OnSelected(RoutedEventArgs e)
{
HandleIsSelectedChanged(true, e);
}
/// <summary>
/// Event indicating that the IsSelected property is now false.
/// </summary>
/// <param name="e">Event arguments</param>
protected virtual void OnUnselected(RoutedEventArgs e)
{
HandleIsSelectedChanged(false, e);
}
private void HandleIsSelectedChanged(bool newValue, RoutedEventArgs e)
{
#if OLD_AUTOMATION
if (AutomationProvider.IsActive)
{
RaiseAutomationIsSelectedChanged(!newValue, newValue);
}
#endif
RaiseEvent(e);
}
#if OLD_AUTOMATION
[System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)]
private void RaiseAutomationIsSelectedChanged(bool oldValue, bool newValue)
{
AutomationProvider.RaiseAutomationPropertyChangedEvent(this, SelectionItemPatternIdentifiers.IsSelectedProperty, oldValue, newValue);
}
#endif
#region TabStripPlacement
/// <summary>
/// Property key for TabStripPlacementProperty.
/// </summary>
private static readonly DependencyPropertyKey TabStripPlacementPropertyKey =
DependencyProperty.RegisterReadOnly(
"TabStripPlacement",
typeof(Dock),
typeof(TabItem),
new FrameworkPropertyMetadata(
Dock.Top,
null,
new CoerceValueCallback(CoerceTabStripPlacement)));
/// <summary>
/// Specifies the placement of the TabItem
/// </summary>
public static readonly DependencyProperty TabStripPlacementProperty =
TabStripPlacementPropertyKey.DependencyProperty;
private static object CoerceTabStripPlacement(DependencyObject d, object value)
{
TabControl tabControl = ((TabItem)d).TabControlParent;
return (tabControl != null) ? tabControl.TabStripPlacement : value;
}
/// <summary>
/// Specifies the placement of the TabItem. This read-only property get its value from the TabControl parent
/// </summary>
public Dock TabStripPlacement
{
get
{
return (Dock)GetValue(TabStripPlacementProperty);
}
}
internal override void OnAncestorChanged()
{
// TabStripPlacement depends on the logical parent -- so invalidate it when that changes
CoerceValue(TabStripPlacementProperty);
}
#endregion TabStripPlacement
#endregion
//-------------------------------------------------------------------
//
// Protected Methods
//
//-------------------------------------------------------------------
#region Protected Methods
internal override void ChangeVisualState(bool useTransitions)
{
if (!IsEnabled)
{
VisualStateManager.GoToState(this, VisualStates.StateDisabled, useTransitions);
}
else if (IsMouseOver)
{
VisualStateManager.GoToState(this, VisualStates.StateMouseOver, useTransitions);
}
else
{
VisualStateManager.GoToState(this, VisualStates.StateNormal, useTransitions);
}
// Update the SelectionStates group
if (IsSelected)
{
VisualStates.GoToState(this, useTransitions, VisualStates.StateSelected, VisualStates.StateUnselected);
}
else
{
VisualStateManager.GoToState(this, VisualStates.StateUnselected, useTransitions);
}
if (IsKeyboardFocused)
{
VisualStateManager.GoToState(this, VisualStates.StateFocused, useTransitions);
}
else
{
VisualStateManager.GoToState(this, VisualStates.StateUnfocused, useTransitions);
}
base.ChangeVisualState(useTransitions);
}
/// <summary>
/// Creates AutomationPeer (<see cref="UIElement.OnCreateAutomationPeer"/>)
/// </summary>
protected override AutomationPeer OnCreateAutomationPeer()
{
return new TabItemWrapperAutomationPeer(this);
}
/// <summary>
/// This is the method that responds to the MouseLeftButtonDownEvent event.
/// </summary>
/// <param name="e"></param>
protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
{
// We should process only the direct events in case TabItem is the selected one
// otherwise we are getting this event when we click on TabItem content because it is in the logical subtree
if (e.Source == this || !IsSelected)
{
if (SetFocus())
e.Handled = true;
}
base.OnMouseLeftButtonDown(e);
}
/// <summary>
/// Focus event handler
/// </summary>
/// <param name="e"></param>
protected override void OnPreviewGotKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
base.OnPreviewGotKeyboardFocus(e);
if (!e.Handled && e.NewFocus == this)
{
if (FrameworkAppContextSwitches.SelectionPropertiesCanLagBehindSelectionChangedEvent)
{
// old ("useless") behavior - retained for app-compat
if (!IsSelected && TabControlParent != null)
{
SetCurrentValueInternal(IsSelectedProperty, BooleanBoxes.TrueBox);
// If focus moved in result of selection - handle the event to prevent setting focus back on the new item
if (e.OldFocus != Keyboard.FocusedElement)
{
e.Handled = true;
}
else if (GetBoolField(BoolField.SetFocusOnContent))
{
TabControl parentTabControl = TabControlParent;
if (parentTabControl != null)
{
// Save the parent and check for null to make sure that SetCurrentValue didn't have a change handler
// that removed the TabItem from the tree.
ContentPresenter selectedContentPresenter = parentTabControl.SelectedContentPresenter;
if (selectedContentPresenter != null)
{
parentTabControl.UpdateLayout(); // Wait for layout
bool success = selectedContentPresenter.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));
// If we successfully move focus inside the content then don't set focus to the header
if (success)
e.Handled = true;
}
}
}
}
}
else
{
// new behavior. Fixes the case when selection
// changes while focus is in the old SelectedContent
if (!IsSelected && TabControlParent != null)
{
SetCurrentValueInternal(IsSelectedProperty, BooleanBoxes.TrueBox);
// If focus moved in result of selection - handle the event to prevent setting focus back on the new item
if (e.OldFocus != Keyboard.FocusedElement)
{
e.Handled = true;
}
}
if (!e.Handled && GetBoolField(BoolField.SetFocusOnContent))
{
TabControl parentTabControl = TabControlParent;
if (parentTabControl != null)
{
// Save the parent and check for null to make sure that SetCurrentValue didn't have a change handler
// that removed the TabItem from the tree.
ContentPresenter selectedContentPresenter = parentTabControl.SelectedContentPresenter;
if (selectedContentPresenter != null)
{
parentTabControl.UpdateLayout(); // Wait for layout
bool success = selectedContentPresenter.MoveFocus(new TraversalRequest(FocusNavigationDirection.First));
// If we successfully move focus inside the content then don't set focus to the header
if (success)
{
e.Handled = true;
// However, if the focus got switched to a different focus scope,
// mark the header as the one last focused in its focus scope. #8293
if (Keyboard.FocusedElement is DependencyObject focusedElement)
{
DependencyObject thisFocusScope = FocusManager.GetFocusScope(this);
if (thisFocusScope != null && Keyboard.FocusedElement is DependencyObject currentFocus)
{
DependencyObject currentFocusScope = FocusManager.GetFocusScope(currentFocus);
if (currentFocusScope != thisFocusScope && thisFocusScope != null)
FocusManager.SetFocusedElement(thisFocusScope, this);
}
}
}
}
}
}
}
}
}
/// <summary>
/// The Access key for this control was invoked.
/// </summary>
protected override void OnAccessKey(AccessKeyEventArgs e)
{
SetFocus();
}
/// <summary>
/// This method is invoked when the Content property changes.
/// </summary>
/// <param name="oldContent">The old value of the Content property.</param>
/// <param name="newContent">The new value of the Content property.</param>
protected override void OnContentChanged(object oldContent, object newContent)
{
base.OnContentChanged(oldContent, newContent);
// If this is the selected TabItem then we should update TabControl.SelectedContent
if (IsSelected)
{
TabControl tabControl = TabControlParent;
if (tabControl != null)
{
if (newContent == BindingExpressionBase.DisconnectedItem)
{
// don't let {DisconnectedItem} bleed into the UI
newContent = null;
}
tabControl.SelectedContent = newContent;
}
}
}
/// <summary>
/// This method is invoked when the ContentTemplate property changes.
/// </summary>
/// <param name="oldContentTemplate">The old value of the ContentTemplate property.</param>
/// <param name="newContentTemplate">The new value of the ContentTemplate property.</param>
protected override void OnContentTemplateChanged(DataTemplate oldContentTemplate, DataTemplate newContentTemplate)
{
base.OnContentTemplateChanged(oldContentTemplate, newContentTemplate);
// If this is the selected TabItem then we should update TabControl.SelectedContentTemplate
if (IsSelected)
{
TabControl tabControl = TabControlParent;
if (tabControl != null)
{
tabControl.SelectedContentTemplate = newContentTemplate;
}
}
}
/// <summary>
/// This method is invoked when the ContentTemplateSelector property changes.
/// </summary>
/// <param name="oldContentTemplateSelector">The old value of the ContentTemplateSelector property.</param>
/// <param name="newContentTemplateSelector">The new value of the ContentTemplateSelector property.</param>
protected override void OnContentTemplateSelectorChanged(DataTemplateSelector oldContentTemplateSelector, DataTemplateSelector newContentTemplateSelector)
{
base.OnContentTemplateSelectorChanged(oldContentTemplateSelector, newContentTemplateSelector);
// If this is the selected TabItem then we should update TabControl.SelectedContentTemplateSelector
if (IsSelected)
{
TabControl tabControl = TabControlParent;
if (tabControl != null)
{
tabControl.SelectedContentTemplateSelector = newContentTemplateSelector;
}
}
}
#endregion
//-------------------------------------------------------------------
//
// Private Methods
//
//-------------------------------------------------------------------
#region Private Methods
private static void OnAccessKeyPressed(object sender, AccessKeyPressedEventArgs e)
{
if (!e.Handled && e.Scope == null)
{
TabItem tabItem = sender as TabItem;
if (e.Target == null)
{
e.Target = tabItem;
}
else if (!tabItem.IsSelected) // If TabItem is not active it is a scope for its content elements
{
e.Scope = tabItem;
e.Handled = true;
}
}
}
internal bool SetFocus()
{
bool returnValue = false;
if (!GetBoolField(BoolField.SettingFocus))
{
TabItem currentFocus = Keyboard.FocusedElement as TabItem;
// If current focus was another TabItem in the same TabControl - dont set focus on content
bool setFocusOnContent = (FrameworkAppContextSwitches.SelectionPropertiesCanLagBehindSelectionChangedEvent || !IsKeyboardFocusWithin)
&& ((currentFocus == this) || (currentFocus == null) || (currentFocus.TabControlParent != this.TabControlParent));
SetBoolField(BoolField.SettingFocus, true);
SetBoolField(BoolField.SetFocusOnContent, setFocusOnContent);
try
{
returnValue = Focus() || setFocusOnContent;
}
finally
{
SetBoolField(BoolField.SettingFocus, false);
SetBoolField(BoolField.SetFocusOnContent, false);
}
}
return returnValue;
}
private TabControl TabControlParent
{
get
{
return ItemsControl.ItemsControlFromItemContainer(this) as TabControl;
}
}
#endregion
//-------------------------------------------------------------------
//
// Private Fields
//
//-------------------------------------------------------------------
#region Private Fields
private bool GetBoolField(BoolField field)
{
return (_tabItemBoolFieldStore & field) != 0;
}
private void SetBoolField(BoolField field, bool value)
{
if (value)
{
_tabItemBoolFieldStore |= field;
}
else
{
_tabItemBoolFieldStore &= (~field);
}
}
[Flags]
private enum BoolField
{
SetFocusOnContent = 0x10, // This flag determine if we want to set focus on active TabItem content
SettingFocus = 0x20, // This flag indicates that the TabItem is in the process of setting focus
// By default ListBoxItem is selectable
DefaultValue = 0,
}
BoolField _tabItemBoolFieldStore = BoolField.DefaultValue;
#endregion Private Fields
#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
}
}
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