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//---------------------------------------------------------------------------
//
// <copyright file=AdornerDecorator.cs company=Microsoft>
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
//
// Description:
// AdornerDecorator class.
// See spec at: http://avalon/uis/Specs/AdornerLayer%20Spec.htm
//
// History:
// 1/29/2004 psarrett: Created
//
//---------------------------------------------------------------------------
using System;
using System.Collections;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Threading;
namespace System.Windows.Documents
{
/// <summary>
/// This AdornerDecorator does not hookup its child in the logical tree. It's being
/// used by PopupRoot and FixedDocument.
/// </summary>
internal class NonLogicalAdornerDecorator : AdornerDecorator
{
public override UIElement Child
{
get
{
return IntChild;
}
set
{
if (IntChild != value)
{
this.RemoveVisualChild(IntChild);
this.RemoveVisualChild(AdornerLayer);
IntChild = value;
if(value != null)
{
this.AddVisualChild(value);
this.AddVisualChild(AdornerLayer);
}
InvalidateMeasure();
}
}
}
}
/// <summary>
/// Object which allows elements beneath it in the visual tree to be adorned.
/// AdornerDecorator has two children.
/// The first child is the parent of the rest of the visual tree below the AdornerDecorator.
/// The second child is the AdornerLayer on which adorners are rendered.
///
/// AdornerDecorator is intended to be used as part of an object's Style.
/// </summary>
public class AdornerDecorator : Decorator
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
/// <summary>
/// Constructor
/// </summary>
public AdornerDecorator() : base()
{
_adornerLayer = new AdornerLayer();
}
#endregion Constructors
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
//------------------------------------------------------
//
// Public Properties
//
//------------------------------------------------------
#region Public Properties
/// <summary>
/// AdornerLayer on which adorners are rendered.
/// </summary>
public AdornerLayer AdornerLayer
{
get
{
return _adornerLayer;
}
}
#endregion Public Properties
//------------------------------------------------------
//
// Protected Methods
//
//------------------------------------------------------
#region Protected Methods
/// <summary>
/// Measurement override. Implement your size-to-content logic here.
/// </summary>
/// <param name="constraint">
/// Sizing constraint.
/// </param>
protected override Size MeasureOverride(Size constraint)
{
Size desiredSize = base.MeasureOverride(constraint);
if (VisualTreeHelper.GetParent(_adornerLayer) != null)
{
// We don't really care about the size of the AdornerLayer-- we'll
// always just make the AdornerDecorator the full desiredSize. But
// we need to measure it anyway, to make sure Adorners render.
_adornerLayer.Measure(constraint);
}
return desiredSize;
}
/// <summary>
/// Override for <seealso cref="FrameworkElement.ArrangeOverride" />
/// </summary>
/// <param name="finalSize">The size reserved for this element by the parent</param>
/// <returns>The actual ink area of the element, typically the same as finalSize</returns>
protected override Size ArrangeOverride(Size finalSize)
{
Size inkSize = base.ArrangeOverride(finalSize);
if (VisualTreeHelper.GetParent(_adornerLayer) != null)
{
_adornerLayer.Arrange(new Rect(finalSize));
}
return (inkSize);
}
/// <summary>
/// Gets or sets the child of the AdornerDecorator.
/// </summary>
public override UIElement Child
{
get
{
return base.Child;
}
set
{
Visual old = base.Child;
if (old == value)
{
return;
}
if (value == null)
{
base.Child = null;
RemoveVisualChild(_adornerLayer);
}
else
{
base.Child = value;
if (null == old)
{
AddVisualChild(_adornerLayer);
}
}
}
}
/// <summary>
/// Returns the Visual children count.
/// </summary>
protected override int VisualChildrenCount
{
get
{
if (base.Child != null)
{
return 2; // One for the child and one for the adorner layer.
}
else
{
return 0;
}
}
}
/// <summary>
/// Returns the child at the specified index.
/// </summary>
protected override Visual GetVisualChild(int index)
{
if (base.Child == null)
{
throw new ArgumentOutOfRangeException("index", index, SR.Get(SRID.Visual_ArgumentOutOfRange));
}
else
{
switch (index)
{
case 0:
return base.Child;
case 1:
return _adornerLayer;
default:
throw new ArgumentOutOfRangeException("index", index, SR.Get(SRID.Visual_ArgumentOutOfRange));
}
}
}
#endregion Protected Methods
//------------------------------------------------------
//
// Private Members
//
//------------------------------------------------------
#region Private Members
//
// This property
// 1. Finds the correct initial size for the _effectiveValues store on the current DependencyObject
// 2. This is a performance optimization
//
internal override int EffectiveValuesInitialSize
{
get { return 6; }
}
readonly AdornerLayer _adornerLayer;
#endregion Private Members
}
}
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