|
// 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 MS.Internal.KnownBoxes;
using System.Windows.Media;
using System.Windows.Input;
namespace System.Windows.Controls
{
/// <summary>
/// Control that implements a selectable item inside a ComboBox.
/// </summary>
[Localizability(LocalizationCategory.ComboBox)]
#if OLD_AUTOMATION
[Automation(AccessibilityControlType = "ListItem")]
#endif
public class ComboBoxItem : ListBoxItem
{
//-------------------------------------------------------------------
//
// 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 ComboBoxItem() : base()
{
}
static ComboBoxItem()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(ComboBoxItem), new FrameworkPropertyMetadata(typeof(ComboBoxItem)));
_dType = DependencyObjectType.FromSystemTypeInternal(typeof(ComboBoxItem));
}
#endregion
#region Public Properties
/// <summary>
/// The key needed set a read-only property.
/// </summary>
private static readonly DependencyPropertyKey IsHighlightedPropertyKey =
DependencyProperty.RegisterReadOnly("IsHighlighted", typeof(bool), typeof(ComboBoxItem),
new FrameworkPropertyMetadata(BooleanBoxes.FalseBox));
/// <summary>
/// DependencyProperty for the IsHighlighted property
/// </summary>
public static readonly DependencyProperty IsHighlightedProperty =
IsHighlightedPropertyKey.DependencyProperty;
/// <summary>
/// Indicates if the item is highlighted or not. Styles that want to
/// show a highlight for selection should trigger off of this value.
/// </summary>
/// <value></value>
public bool IsHighlighted
{
get
{
return (bool)GetValue(IsHighlightedProperty);
}
protected set
{
SetValue(IsHighlightedPropertyKey, BooleanBoxes.Box(value));
}
}
#endregion
//-------------------------------------------------------------------
//
// Protected Methods
//
//-------------------------------------------------------------------
#region Protected Methods
/// <summary>
/// This is the method that responds to the MouseButtonEvent event.
/// </summary>
/// <param name="e">Event arguments</param>
protected override void OnMouseLeftButtonDown(MouseButtonEventArgs e)
{
e.Handled = true;
ComboBox parent = ParentComboBox;
if (parent != null)
{
parent.NotifyComboBoxItemMouseDown(this);
}
base.OnMouseLeftButtonDown(e);
}
/// <summary>
///
/// </summary>
/// <param name="e"></param>
protected override void OnMouseLeftButtonUp(MouseButtonEventArgs e)
{
e.Handled = true;
ComboBox parent = ParentComboBox;
if (parent != null)
{
parent.NotifyComboBoxItemMouseUp(this);
}
base.OnMouseLeftButtonUp(e);
}
/// <summary>
///
/// </summary>
/// <param name="e"></param>
protected override void OnMouseEnter(MouseEventArgs e)
{
e.Handled = true;
ComboBox parent = ParentComboBox;
if (parent != null)
{
parent.NotifyComboBoxItemEnter(this);
}
base.OnMouseEnter(e);
}
/// <summary>
/// Called when Content property has been changed.
/// </summary>
/// <param name="oldContent"></param>
/// <param name="newContent"></param>
protected override void OnContentChanged(object oldContent, object newContent)
{
base.OnContentChanged(oldContent, newContent);
// If this is selected, we need to update ParentComboBox.Text
// Scenario:
// <ComboBox Width="200" Height="20" IsEditable="True" MaxDropDownHeight="50">
// <Text>item1</Text>
// <Text>Item2</Text>
// <ComboBoxItem IsSelected="True">item3</ComboBoxItem>
// </ComboBox>
// In this case ComboBox will try to update Text property as soon as it get
// SelectionChanged event. However, at that time ComboBoxItem.Content is not
// parse yet. So, Content is null. This causes ComboBox.Text to be "".
//
ComboBox parent;
if (IsSelected && (null != (parent = ParentComboBox)))
{
parent.SelectedItemUpdated();
}
// When the content of the combobox item is a UIElement,
// combobox will create a visual clone of the item which needs
// to update even when the combobox is closed
SetFlags(newContent is UIElement, VisualFlags.IsLayoutIslandRoot);
}
/// <summary>
/// Called when this element gets focus.
/// </summary>
/// <param name="e"></param>
protected override void OnGotKeyboardFocus(KeyboardFocusChangedEventArgs e)
{
e.Handled = true;
ComboBox parent = ParentComboBox;
if (parent != null)
{
parent.NotifyComboBoxItemEnter(this);
}
base.OnGotKeyboardFocus(e);
}
#endregion
//-------------------------------------------------------------------
//
// Implementation
//
//-------------------------------------------------------------------
#region Implementation
private ComboBox ParentComboBox
{
get
{
return ParentSelector as ComboBox;
}
}
internal void SetIsHighlighted(bool isHighlighted)
{
IsHighlighted = isHighlighted;
}
#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
}
}
|