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//---------------------------------------------------------------------------
//
// <copyright file="ItemsPanelTemplate.cs" company="Microsoft">
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
// Description: ItemsPanelTemplate describes how ItemsPresenter creates the panel
// that manages layout of containers for an ItemsControl.
//
// Specs:
//
//---------------------------------------------------------------------------
using System.ComponentModel;
using System.Windows.Controls;
using System.Windows.Markup;
using System.Diagnostics;
namespace System.Windows.Controls
{
/// <summary>
/// ItemsPanelTemplate describes how ItemsPresenter creates the panel
/// that manages layout of containers for an ItemsControl.
/// </summary>
public class ItemsPanelTemplate : FrameworkTemplate
{
#region Constructors
//-------------------------------------------------------------------
//
// Constructors
//
//-------------------------------------------------------------------
/// <summary>
/// ItemsPanelTemplate Constructor
/// </summary>
public ItemsPanelTemplate()
{
}
/// <summary>
/// ItemsPanelTemplate Constructor
/// </summary>
public ItemsPanelTemplate(FrameworkElementFactory root)
{
VisualTree = root;
}
#endregion Constructors
#region Public Properties
//-------------------------------------------------------------------
//
// Public Properties
//
//-------------------------------------------------------------------
#endregion PublicProperties
#region Internal Properties
//-------------------------------------------------------------------
//
// Internal Properties
//
//-------------------------------------------------------------------
//
// TargetType for ItemsPanelTemplate. This is override is
// so FrameworkTemplate can see this property.
//
internal override Type TargetTypeInternal
{
get { return DefaultTargetType; }
}
// Subclasses must provide a way for the parser to directly set the
// target type. For ItemsPanelTemplate, this is not allowed.
internal override void SetTargetTypeInternal(Type targetType)
{
throw new InvalidOperationException(SR.Get(SRID.TemplateNotTargetType));
}
// Target type of ItemsPanelTemplate is ItemsPresenter
static internal Type DefaultTargetType
{
get { return typeof(ItemsPresenter); }
}
#endregion Internal Properties
#region Internal Methods
//-------------------------------------------------------------------
//
// Internal Methods
//
//-------------------------------------------------------------------
//
// ProcessTemplateBeforeSeal
//
// This is used in the case of templates defined with FEFs. For templates
// in Baml (the typical case), see the OnApply override.
//
// 1. Verify that
// a. root element is a Panel
// 2. Set IsItemsHost = true
//
internal override void ProcessTemplateBeforeSeal()
{
FrameworkElementFactory root;
if( HasContent )
{
// This is a Baml-style template
// Validate the root type (it must be a Panel)
TemplateContent templateHolder = Template as TemplateContent;
System.Xaml.XamlType panelType = templateHolder.SchemaContext.GetXamlType(typeof(Panel));
if (templateHolder.RootType == null || !templateHolder.RootType.CanAssignTo(panelType))
{
throw new InvalidOperationException(SR.Get(SRID.ItemsPanelNotAPanel, templateHolder.RootType));
}
}
else if ((root = this.VisualTree) != null)
{
// This is a FEF-style template
if (!typeof(Panel).IsAssignableFrom(root.Type))
throw new InvalidOperationException(SR.Get(SRID.ItemsPanelNotAPanel, root.Type));
root.SetValue(Panel.IsItemsHostProperty, true);
}
}
#endregion Internal Methods
#region Protected Methods
//-------------------------------------------------------------------
//
// Protected Methods
//
//-------------------------------------------------------------------
/// <summary>
/// Validate against the following rules
/// 1. Must have a non-null feTemplatedParent
/// 2. A ItemsPanelTemplate must be applied to a ContentPresenter
/// </summary>
protected override void ValidateTemplatedParent(FrameworkElement templatedParent)
{
// Must have a non-null feTemplatedParent
if (templatedParent == null)
{
throw new ArgumentNullException("templatedParent");
}
// A ItemsPanelTemplate must be applied to an ItemsPresenter
if (!(templatedParent is ItemsPresenter))
{
throw new ArgumentException(SR.Get(SRID.TemplateTargetTypeMismatch, "ItemsPresenter", templatedParent.GetType().Name));
}
}
#endregion Protected Methods
}
}
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