Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Controls / ItemsPresenter.cs / 1305600 / ItemsPresenter.cs
//----------------------------------------------------------------------------
//
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
//
// Description: ItemsPresenter object - site of the panel for layout of groups or items.
//
// Specs: http://avalon/connecteddata/M5%20General%20Docs/Data%20Styling.mht
//
//---------------------------------------------------------------------------
using System;
using System.Collections;
using System.Diagnostics;
using System.Windows.Media;
using MS.Internal;
using MS.Internal.Data; // WeakRefKey
namespace System.Windows.Controls
{
///
/// An ItemsPresenter marks the site (in a style) of the panel that controls
/// layout of groups or items.
///
[Localizability(LocalizationCategory.NeverLocalize)]
public class ItemsPresenter : FrameworkElement
{
//-----------------------------------------------------
//
// Public Methods
//
//-----------------------------------------------------
///
/// Called when the Template's tree is about to be generated
///
internal override void OnPreApplyTemplate()
{
base.OnPreApplyTemplate();
AttachToOwner();
}
///
/// This is the virtual that sub-classes must override if they wish to get
/// notified that the template tree has been created.
///
public override void OnApplyTemplate()
{
// verify that the template produced a panel with no children
Panel panel = GetVisualChild(0) as Panel;
if (panel == null || VisualTreeHelper.GetChildrenCount(panel) > 0)
throw new InvalidOperationException(SR.Get(SRID.ItemsPanelNotSingleNode));
base.OnApplyTemplate();
}
//------------------------------------------------------
//
// Protected Methods
//
//-----------------------------------------------------
///
/// Override of
/// Constraint size is an "upper limit" that the return value should not exceed.
/// The ItemsPresenter's desired size.
protected override Size MeasureOverride(Size constraint)
{
return Helper.MeasureElementWithSingleChild(this, constraint);
}
///
/// Override of
/// Size the ItemsPresenter will assume.
protected override Size ArrangeOverride(Size arrangeSize)
{
return Helper.ArrangeElementWithSingleChild(this, arrangeSize);
}
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
internal ItemsControl Owner
{
get { return _owner; }
}
internal ItemContainerGenerator Generator
{
get { return _generator; }
}
// Internal Helper so the FrameworkElement could see this property
internal override FrameworkTemplate TemplateInternal
{
get { return Template; }
}
// Internal Helper so the FrameworkElement could see the template cache
internal override FrameworkTemplate TemplateCache
{
get { return _templateCache; }
set { _templateCache = (ItemsPanelTemplate)value; }
}
///
/// TemplateProperty
///
internal static readonly DependencyProperty TemplateProperty =
DependencyProperty.Register(
"Template",
typeof(ItemsPanelTemplate),
typeof(ItemsPresenter),
new FrameworkPropertyMetadata(
(ItemsPanelTemplate) null, // default value
FrameworkPropertyMetadataOptions.AffectsMeasure,
new PropertyChangedCallback(OnTemplateChanged)));
///
/// Template Property
///
private ItemsPanelTemplate Template
{
get { return _templateCache; }
set { SetValue(TemplateProperty, value); }
}
// Internal helper so FrameworkElement could see call the template changed virtual
internal override void OnTemplateChangedInternal(FrameworkTemplate oldTemplate, FrameworkTemplate newTemplate)
{
OnTemplateChanged((ItemsPanelTemplate)oldTemplate, (ItemsPanelTemplate)newTemplate);
}
// Property invalidation callback invoked when TemplateProperty is invalidated
private static void OnTemplateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ItemsPresenter ip = (ItemsPresenter) d;
StyleHelper.UpdateTemplateCache(ip, (FrameworkTemplate) e.OldValue, (FrameworkTemplate) e.NewValue, TemplateProperty);
}
///
/// Template has changed
///
///
/// When a Template changes, the VisualTree is removed. The new Template's
/// VisualTree will be created when ApplyTemplate is called
///
/// The old Template
/// The new Template
protected virtual void OnTemplateChanged(ItemsPanelTemplate oldTemplate, ItemsPanelTemplate newTemplate)
{
}
//-----------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
internal static ItemsPresenter FromPanel(Panel panel)
{
if (panel == null)
return null;
return panel.TemplatedParent as ItemsPresenter;
}
internal static ItemsPresenter FromGroupItem(GroupItem groupItem)
{
if (groupItem == null)
return null;
Visual parent = VisualTreeHelper.GetParent(groupItem) as Visual;
if (parent == null)
return null;
return VisualTreeHelper.GetParent(parent) as ItemsPresenter;
}
internal override void OnAncestorChanged()
{
if (TemplatedParent == null)
{
UseGenerator(null);
ClearPanel();
}
base.OnAncestorChanged();
}
//-----------------------------------------------------
//
// Private Methods
//
//-----------------------------------------------------
// initialize (called during measure, from ApplyTemplate)
void AttachToOwner()
{
ItemsControl owner = this.TemplatedParent as ItemsControl;
ItemContainerGenerator generator;
if (owner != null)
{
// top-level presenter - get information from ItemsControl
generator = owner.ItemContainerGenerator;
}
else
{
// subgroup presenter - get information from GroupItem
GroupItem parentGI = this.TemplatedParent as GroupItem;
ItemsPresenter parentIP = FromGroupItem(parentGI);
if (parentIP != null)
owner = parentIP.Owner;
generator = (parentGI != null) ? parentGI.Generator : null;
}
_owner = owner;
UseGenerator(generator);
// create the panel, based either on ItemsControl.ItemsPanel or GroupStyle.Panel
GroupStyle groupStyle = (_generator != null) ? _generator.GroupStyle : null;
Template = (groupStyle != null) ? groupStyle.Panel
: (_owner != null) ? _owner.ItemsPanel
: null;
}
void UseGenerator(ItemContainerGenerator generator)
{
if (generator == _generator)
return;
if (_generator != null)
_generator.PanelChanged -= new EventHandler(OnPanelChanged);
_generator = generator;
if (_generator != null)
_generator.PanelChanged += new EventHandler(OnPanelChanged);
}
private void OnPanelChanged(object sender, EventArgs e)
{
// something has changed that affects the ItemsPresenter.
// Re-measure. This will recalculate everything from scratch.
InvalidateMeasure();
//
// If we're under a ScrollViewer then its ScrollContentPresenter needs to
// be updated to work with the new panel.
//
ScrollViewer parent = Parent as ScrollViewer;
if (parent != null)
{
// If our logical parent is a ScrollViewer then the visual parent is a ScrollContentPresenter.
ScrollContentPresenter scp = VisualTreeHelper.GetParent(this) as ScrollContentPresenter;
if (scp != null)
{
scp.HookupScrollingComponents();
}
}
}
// workaround, pending bug 953483. The panel is
// being removed from the tree, so it should release
// its resources (chiefly - stop listening for generator's
// ItemsChanged event). Until there's a mechanism for
// this, just mark the panel as a non-ItemsHost, so
// that the next time it gets ItemsChanged it will
// stop listening. (See also bug 942265)
private void ClearPanel()
{
Panel oldPanel = (this.VisualChildrenCount > 0) ? this.GetVisualChild(0) as Panel : null;
Type type = null;
if( Template != null )
{
// Get the type of the template content's root
// Is this a FEF-based template?
if( Template.VisualTree != null )
{
type = Template.VisualTree.Type;
}
// Or, is it a (non-empty) Baml-based template?
else if (Template.HasXamlNodeContent)
{
System.Xaml.XamlType xType = (Template.Template as TemplateContent).RootType;
type = xType.UnderlyingType;
}
}
if (oldPanel != null && oldPanel.GetType() == type)
{
oldPanel.IsItemsHost = false;
}
}
//-----------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
ItemsControl _owner;
ItemContainerGenerator _generator;
ItemsPanelTemplate _templateCache;
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
//----------------------------------------------------------------------------
//
//
// Copyright (C) Microsoft Corporation. All rights reserved.
//
//
// Description: ItemsPresenter object - site of the panel for layout of groups or items.
//
// Specs: http://avalon/connecteddata/M5%20General%20Docs/Data%20Styling.mht
//
//---------------------------------------------------------------------------
using System;
using System.Collections;
using System.Diagnostics;
using System.Windows.Media;
using MS.Internal;
using MS.Internal.Data; // WeakRefKey
namespace System.Windows.Controls
{
///
/// An ItemsPresenter marks the site (in a style) of the panel that controls
/// layout of groups or items.
///
[Localizability(LocalizationCategory.NeverLocalize)]
public class ItemsPresenter : FrameworkElement
{
//-----------------------------------------------------
//
// Public Methods
//
//-----------------------------------------------------
///
/// Called when the Template's tree is about to be generated
///
internal override void OnPreApplyTemplate()
{
base.OnPreApplyTemplate();
AttachToOwner();
}
///
/// This is the virtual that sub-classes must override if they wish to get
/// notified that the template tree has been created.
///
public override void OnApplyTemplate()
{
// verify that the template produced a panel with no children
Panel panel = GetVisualChild(0) as Panel;
if (panel == null || VisualTreeHelper.GetChildrenCount(panel) > 0)
throw new InvalidOperationException(SR.Get(SRID.ItemsPanelNotSingleNode));
base.OnApplyTemplate();
}
//------------------------------------------------------
//
// Protected Methods
//
//-----------------------------------------------------
///
/// Override of
/// Constraint size is an "upper limit" that the return value should not exceed.
/// The ItemsPresenter's desired size.
protected override Size MeasureOverride(Size constraint)
{
return Helper.MeasureElementWithSingleChild(this, constraint);
}
///
/// Override of
/// Size the ItemsPresenter will assume.
protected override Size ArrangeOverride(Size arrangeSize)
{
return Helper.ArrangeElementWithSingleChild(this, arrangeSize);
}
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
internal ItemsControl Owner
{
get { return _owner; }
}
internal ItemContainerGenerator Generator
{
get { return _generator; }
}
// Internal Helper so the FrameworkElement could see this property
internal override FrameworkTemplate TemplateInternal
{
get { return Template; }
}
// Internal Helper so the FrameworkElement could see the template cache
internal override FrameworkTemplate TemplateCache
{
get { return _templateCache; }
set { _templateCache = (ItemsPanelTemplate)value; }
}
///
/// TemplateProperty
///
internal static readonly DependencyProperty TemplateProperty =
DependencyProperty.Register(
"Template",
typeof(ItemsPanelTemplate),
typeof(ItemsPresenter),
new FrameworkPropertyMetadata(
(ItemsPanelTemplate) null, // default value
FrameworkPropertyMetadataOptions.AffectsMeasure,
new PropertyChangedCallback(OnTemplateChanged)));
///
/// Template Property
///
private ItemsPanelTemplate Template
{
get { return _templateCache; }
set { SetValue(TemplateProperty, value); }
}
// Internal helper so FrameworkElement could see call the template changed virtual
internal override void OnTemplateChangedInternal(FrameworkTemplate oldTemplate, FrameworkTemplate newTemplate)
{
OnTemplateChanged((ItemsPanelTemplate)oldTemplate, (ItemsPanelTemplate)newTemplate);
}
// Property invalidation callback invoked when TemplateProperty is invalidated
private static void OnTemplateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ItemsPresenter ip = (ItemsPresenter) d;
StyleHelper.UpdateTemplateCache(ip, (FrameworkTemplate) e.OldValue, (FrameworkTemplate) e.NewValue, TemplateProperty);
}
///
/// Template has changed
///
///
/// When a Template changes, the VisualTree is removed. The new Template's
/// VisualTree will be created when ApplyTemplate is called
///
/// The old Template
/// The new Template
protected virtual void OnTemplateChanged(ItemsPanelTemplate oldTemplate, ItemsPanelTemplate newTemplate)
{
}
//-----------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
internal static ItemsPresenter FromPanel(Panel panel)
{
if (panel == null)
return null;
return panel.TemplatedParent as ItemsPresenter;
}
internal static ItemsPresenter FromGroupItem(GroupItem groupItem)
{
if (groupItem == null)
return null;
Visual parent = VisualTreeHelper.GetParent(groupItem) as Visual;
if (parent == null)
return null;
return VisualTreeHelper.GetParent(parent) as ItemsPresenter;
}
internal override void OnAncestorChanged()
{
if (TemplatedParent == null)
{
UseGenerator(null);
ClearPanel();
}
base.OnAncestorChanged();
}
//-----------------------------------------------------
//
// Private Methods
//
//-----------------------------------------------------
// initialize (called during measure, from ApplyTemplate)
void AttachToOwner()
{
ItemsControl owner = this.TemplatedParent as ItemsControl;
ItemContainerGenerator generator;
if (owner != null)
{
// top-level presenter - get information from ItemsControl
generator = owner.ItemContainerGenerator;
}
else
{
// subgroup presenter - get information from GroupItem
GroupItem parentGI = this.TemplatedParent as GroupItem;
ItemsPresenter parentIP = FromGroupItem(parentGI);
if (parentIP != null)
owner = parentIP.Owner;
generator = (parentGI != null) ? parentGI.Generator : null;
}
_owner = owner;
UseGenerator(generator);
// create the panel, based either on ItemsControl.ItemsPanel or GroupStyle.Panel
GroupStyle groupStyle = (_generator != null) ? _generator.GroupStyle : null;
Template = (groupStyle != null) ? groupStyle.Panel
: (_owner != null) ? _owner.ItemsPanel
: null;
}
void UseGenerator(ItemContainerGenerator generator)
{
if (generator == _generator)
return;
if (_generator != null)
_generator.PanelChanged -= new EventHandler(OnPanelChanged);
_generator = generator;
if (_generator != null)
_generator.PanelChanged += new EventHandler(OnPanelChanged);
}
private void OnPanelChanged(object sender, EventArgs e)
{
// something has changed that affects the ItemsPresenter.
// Re-measure. This will recalculate everything from scratch.
InvalidateMeasure();
//
// If we're under a ScrollViewer then its ScrollContentPresenter needs to
// be updated to work with the new panel.
//
ScrollViewer parent = Parent as ScrollViewer;
if (parent != null)
{
// If our logical parent is a ScrollViewer then the visual parent is a ScrollContentPresenter.
ScrollContentPresenter scp = VisualTreeHelper.GetParent(this) as ScrollContentPresenter;
if (scp != null)
{
scp.HookupScrollingComponents();
}
}
}
// workaround, pending bug 953483. The panel is
// being removed from the tree, so it should release
// its resources (chiefly - stop listening for generator's
// ItemsChanged event). Until there's a mechanism for
// this, just mark the panel as a non-ItemsHost, so
// that the next time it gets ItemsChanged it will
// stop listening. (See also bug 942265)
private void ClearPanel()
{
Panel oldPanel = (this.VisualChildrenCount > 0) ? this.GetVisualChild(0) as Panel : null;
Type type = null;
if( Template != null )
{
// Get the type of the template content's root
// Is this a FEF-based template?
if( Template.VisualTree != null )
{
type = Template.VisualTree.Type;
}
// Or, is it a (non-empty) Baml-based template?
else if (Template.HasXamlNodeContent)
{
System.Xaml.XamlType xType = (Template.Template as TemplateContent).RootType;
type = xType.UnderlyingType;
}
}
if (oldPanel != null && oldPanel.GetType() == type)
{
oldPanel.IsItemsHost = false;
}
}
//-----------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
ItemsControl _owner;
ItemContainerGenerator _generator;
ItemsPanelTemplate _templateCache;
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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