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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.Collections;
using System.ComponentModel;
using System.Windows.Data;
using System.Windows.Markup;
using MS.Internal;
using MS.Internal.Controls;
using MS.Internal.KnownBoxes;
using MS.Internal.PresentationFramework;
using MS.Internal.Telemetry.PresentationFramework;
namespace System.Windows.Controls
{
/// <summary>
/// The base class for all controls with a single piece of content.
/// </summary>
/// <remarks>
/// ContentControl adds Content, ContentTemplate, ContentTemplateSelector and Part features to a Control.
/// </remarks>
[DefaultProperty("Content")]
[ContentProperty("Content")]
[Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)]
public class ContentControl : Control, IAddChild
{
#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 ContentControl() : base()
{
}
static ContentControl()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(ContentControl), new FrameworkPropertyMetadata(typeof(ContentControl)));
_dType = DependencyObjectType.FromSystemTypeInternal(typeof(ContentControl));
ControlsTraceLogger.AddControl(TelemetryControls.ContentControl);
}
#endregion
#region LogicalTree
/// <summary>
/// Returns enumerator to logical children
/// </summary>
protected internal override IEnumerator LogicalChildren
{
get
{
object content = Content;
if (ContentIsNotLogical || content == null)
{
return EmptyEnumerator.Instance;
}
// If the current ContentControl is in a Template.VisualTree and is meant to host
// the content for the container then that content shows up as the logical child
// for the container and not for the current ContentControl.
DependencyObject templatedParent = this.TemplatedParent;
if (templatedParent != null)
{
DependencyObject d = content as DependencyObject;
if (d != null)
{
DependencyObject logicalParent = LogicalTreeHelper.GetParent(d);
if (logicalParent != null && logicalParent != this)
{
return EmptyEnumerator.Instance;
}
}
}
return new ContentModelTreeEnumerator(this, content);
}
}
#endregion
#region Internal Methods
/// <summary>
/// Gives a string representation of this object.
/// </summary>
/// <returns></returns>
internal override string GetPlainText()
{
return ContentObjectToString(Content);
}
internal static string ContentObjectToString(object content)
{
if (content != null)
{
FrameworkElement feContent = content as FrameworkElement;
if (feContent != null)
{
return feContent.GetPlainText();
}
return content.ToString();
}
return String.Empty;
}
/// <summary>
/// Prepare to display the item.
/// </summary>
internal void PrepareContentControl(object item,
DataTemplate itemTemplate,
DataTemplateSelector itemTemplateSelector,
string itemStringFormat)
{
if (item != this)
{
// don't treat Content as a logical child
ContentIsNotLogical = true;
// copy styles from the ItemsControl
if (ContentIsItem || !HasNonDefaultValue(ContentProperty))
{
Content = item;
ContentIsItem = true;
}
if (itemTemplate != null)
SetValue(ContentTemplateProperty, itemTemplate);
if (itemTemplateSelector != null)
SetValue(ContentTemplateSelectorProperty, itemTemplateSelector);
if (itemStringFormat != null)
SetValue(ContentStringFormatProperty, itemStringFormat);
}
else
{
ContentIsNotLogical = false;
}
}
/// <summary>
/// Undo the effect of PrepareContentControl.
/// </summary>
internal void ClearContentControl(object item)
{
if (item != this)
{
if (ContentIsItem)
{
Content = BindingExpressionBase.DisconnectedItem;
}
}
}
/// <summary>
/// This method is used by TypeDescriptor to determine if this property should
/// be serialized.
/// </summary>
// Lets derived classes control the serialization behavior for Content DP
[EditorBrowsable(EditorBrowsableState.Never)]
public virtual bool ShouldSerializeContent()
{
return ReadLocalValue(ContentProperty) != DependencyProperty.UnsetValue;
}
#endregion
#region IAddChild
/// <summary>
/// Add an object child to this control
/// </summary>
void IAddChild.AddChild(object value)
{
AddChild(value);
}
/// <summary>
/// Add an object child to this control
/// </summary>
protected virtual void AddChild(object value)
{
// if conent is the first child or being cleared, set directly
if (Content == null || value == null)
{
Content = value;
}
else
{
throw new InvalidOperationException(SR.ContentControlCannotHaveMultipleContent);
}
}
/// <summary>
/// Add a text string to this control
/// </summary>
void IAddChild.AddText(string text)
{
AddText(text);
}
/// <summary>
/// Add a text string to this control
/// </summary>
protected virtual void AddText(string text)
{
AddChild(text);
}
#endregion IAddChild
#region Properties
/// <summary>
/// The DependencyProperty for the Content property.
/// Flags: None
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ContentProperty =
DependencyProperty.Register(
"Content",
typeof(object),
typeof(ContentControl),
new FrameworkPropertyMetadata(
(object)null,
new PropertyChangedCallback(OnContentChanged)));
/// <summary>
/// Content is the data used to generate the child elements of this control.
/// </summary>
[Bindable(true), CustomCategory("Content")]
public object Content
{
get { return GetValue(ContentProperty); }
set { SetValue(ContentProperty, value); }
}
/// <summary>
/// Called when ContentProperty is invalidated on "d."
/// </summary>
private static void OnContentChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ContentControl ctrl = (ContentControl) d;
ctrl.SetValue(HasContentPropertyKey, (e.NewValue != null) ? BooleanBoxes.TrueBox : BooleanBoxes.FalseBox);
ctrl.OnContentChanged(e.OldValue, e.NewValue);
}
/// <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 virtual void OnContentChanged(object oldContent, object newContent)
{
// Remove the old content child
RemoveLogicalChild(oldContent);
// if Content should not be treated as a logical child, there's
// nothing to do
if (ContentIsNotLogical)
return;
DependencyObject d = newContent as DependencyObject;
if (d != null)
{
DependencyObject logicalParent = LogicalTreeHelper.GetParent(d);
if (logicalParent != null)
{
if (TemplatedParent != null && FrameworkObject.IsEffectiveAncestor(logicalParent, this))
{
// In the case that this ContentControl belongs in a parent template
// and represents the content of a parent, we do not wish to change
// the logical ancestry of the content.
return;
}
else
{
// If the new content was previously hooked up to the logical
// tree then we sever it from the old parent.
LogicalTreeHelper.RemoveLogicalChild(logicalParent, newContent);
}
}
}
// Add the new content child
AddLogicalChild(newContent);
}
/// <summary>
/// The key needed set a read-only property.
/// </summary>
private static readonly DependencyPropertyKey HasContentPropertyKey =
DependencyProperty.RegisterReadOnly(
"HasContent",
typeof(bool),
typeof(ContentControl),
new FrameworkPropertyMetadata(
BooleanBoxes.FalseBox,
FrameworkPropertyMetadataOptions.None));
/// <summary>
/// The DependencyProperty for the HasContent property.
/// Flags: None
/// Other: Read-Only
/// Default Value: false
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty HasContentProperty =
HasContentPropertyKey.DependencyProperty;
/// <summary>
/// True if Content is non-null, false otherwise.
/// </summary>
[Browsable(false), ReadOnly(true)]
public bool HasContent
{
get { return (bool) GetValue(HasContentProperty); }
}
/// <summary>
/// The DependencyProperty for the ContentTemplate property.
/// Flags: None
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ContentTemplateProperty =
DependencyProperty.Register(
"ContentTemplate",
typeof(DataTemplate),
typeof(ContentControl),
new FrameworkPropertyMetadata(
(DataTemplate) null,
new PropertyChangedCallback(OnContentTemplateChanged)));
/// <summary>
/// ContentTemplate is the template used to display the content of the control.
/// </summary>
[Bindable(true), CustomCategory("Content")]
public DataTemplate ContentTemplate
{
get { return (DataTemplate) GetValue(ContentTemplateProperty); }
set { SetValue(ContentTemplateProperty, value); }
}
/// <summary>
/// Called when ContentTemplateProperty is invalidated on "d."
/// </summary>
private static void OnContentTemplateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ContentControl ctrl = (ContentControl)d;
ctrl.OnContentTemplateChanged((DataTemplate) e.OldValue, (DataTemplate) e.NewValue);
}
/// <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 virtual void OnContentTemplateChanged(DataTemplate oldContentTemplate, DataTemplate newContentTemplate)
{
Helper.CheckTemplateAndTemplateSelector("Content", ContentTemplateProperty, ContentTemplateSelectorProperty, this);
}
/// <summary>
/// The DependencyProperty for the ContentTemplateSelector property.
/// Flags: None
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ContentTemplateSelectorProperty =
DependencyProperty.Register(
"ContentTemplateSelector",
typeof(DataTemplateSelector),
typeof(ContentControl),
new FrameworkPropertyMetadata(
(DataTemplateSelector) null,
new PropertyChangedCallback(OnContentTemplateSelectorChanged)));
/// <summary>
/// ContentTemplateSelector allows the application writer to provide custom logic
/// for choosing the template used to display the content of the control.
/// </summary>
/// <remarks>
/// This property is ignored if <seealso cref="ContentTemplate"/> is set.
/// </remarks>
[Bindable(true), CustomCategory("Content")]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public DataTemplateSelector ContentTemplateSelector
{
get { return (DataTemplateSelector) GetValue(ContentTemplateSelectorProperty); }
set { SetValue(ContentTemplateSelectorProperty, value); }
}
/// <summary>
/// Called when ContentTemplateSelectorProperty is invalidated on "d."
/// </summary>
private static void OnContentTemplateSelectorChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ContentControl ctrl = (ContentControl) d;
ctrl.OnContentTemplateSelectorChanged((DataTemplateSelector) e.NewValue, (DataTemplateSelector) e.NewValue);
}
/// <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 virtual void OnContentTemplateSelectorChanged(DataTemplateSelector oldContentTemplateSelector, DataTemplateSelector newContentTemplateSelector)
{
Helper.CheckTemplateAndTemplateSelector("Content", ContentTemplateProperty, ContentTemplateSelectorProperty, this);
}
/// <summary>
/// The DependencyProperty for the ContentStringFormat property.
/// Flags: None
/// Default Value: null
/// </summary>
[CommonDependencyProperty]
public static readonly DependencyProperty ContentStringFormatProperty =
DependencyProperty.Register(
"ContentStringFormat",
typeof(String),
typeof(ContentControl),
new FrameworkPropertyMetadata(
(String) null,
new PropertyChangedCallback(OnContentStringFormatChanged)));
/// <summary>
/// ContentStringFormat is the format used to display the content of
/// the control as a string. This arises only when no template is
/// available.
/// </summary>
[Bindable(true), CustomCategory("Content")]
public String ContentStringFormat
{
get { return (String) GetValue(ContentStringFormatProperty); }
set { SetValue(ContentStringFormatProperty, value); }
}
/// <summary>
/// Called when ContentStringFormatProperty is invalidated on "d."
/// </summary>
private static void OnContentStringFormatChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ContentControl ctrl = (ContentControl)d;
ctrl.OnContentStringFormatChanged((String) e.OldValue, (String) e.NewValue);
}
/// <summary>
/// This method is invoked when the ContentStringFormat property changes.
/// </summary>
/// <param name="oldContentStringFormat">The old value of the ContentStringFormat property.</param>
/// <param name="newContentStringFormat">The new value of the ContentStringFormat property.</param>
protected virtual void OnContentStringFormatChanged(String oldContentStringFormat, String newContentStringFormat)
{
}
#endregion
#region Private methods
//
// Private Methods
//
/// <summary>
/// Indicates whether Content should be a logical child or not.
/// </summary>
internal bool ContentIsNotLogical
{
get { return ReadControlFlag(ControlBoolFlags.ContentIsNotLogical); }
set { WriteControlFlag(ControlBoolFlags.ContentIsNotLogical, value); }
}
/// <summary>
/// Indicates whether Content is a data item
/// </summary>
internal bool ContentIsItem
{
get { return ReadControlFlag(ControlBoolFlags.ContentIsItem); }
set { WriteControlFlag(ControlBoolFlags.ContentIsItem, value); }
}
//
// 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 4; }
}
#endregion Private methods
#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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