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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.
/***************************************************************************\
*
*
* This object includes a named Storyboard references. When triggered, the
* name is resolved and passed to a derived class method to perform the
* actual action.
*
*
\***************************************************************************/
using System.ComponentModel; // DefaultValueAttribute
using System.Windows.Markup; // INameScope
namespace System.Windows.Media.Animation
{
/// <summary>
/// A controllable storyboard action associates a trigger action with a
/// Storyboard. The association from this object is a string that is the name
/// of the Storyboard in a resource dictionary.
/// </summary>
public abstract class ControllableStoryboardAction : TriggerAction
{
/// <summary>
/// Internal constructor - nobody is supposed to ever create an instance
/// of this class. Use a derived class instead.
/// </summary>
internal ControllableStoryboardAction()
{
}
/// <summary>
/// Name to use for resolving the storyboard reference needed. This
/// points to a BeginStoryboard instance, and we're controlling that one.
/// </summary>
[DefaultValue(null)]
public string BeginStoryboardName
{
get
{
return _beginStoryboardName;
}
set
{
if (IsSealed)
{
throw new InvalidOperationException(SR.Format(SR.CannotChangeAfterSealed, "ControllableStoryboardAction"));
}
// Null is allowed to wipe out existing name - as long as another
// valid name is set before Invoke time.
_beginStoryboardName = value;
}
}
internal sealed override void Invoke( FrameworkElement fe, FrameworkContentElement fce, Style targetStyle, FrameworkTemplate frameworkTemplate, Int64 layer )
{
Debug.Assert( fe != null || fce != null, "Caller of internal function failed to verify that we have a FE or FCE - we have neither." );
Debug.Assert( targetStyle != null || frameworkTemplate != null,
"This function expects to be called when the associated action is inside a Style/Template. But it was not given a reference to anything." );
INameScope nameScope = null;
if( targetStyle != null )
{
nameScope = targetStyle;
}
else
{
Debug.Assert( frameworkTemplate != null );
nameScope = frameworkTemplate;
}
Invoke( fe, fce, GetStoryboard( fe, fce, nameScope ) );
}
internal sealed override void Invoke( FrameworkElement fe )
{
Debug.Assert( fe != null, "Invoke needs an object as starting point");
Invoke( fe, null, GetStoryboard( fe, null, null ) );
}
internal virtual void Invoke( FrameworkElement containingFE, FrameworkContentElement containingFCE, Storyboard storyboard )
{
}
// Find a Storyboard object for this StoryboardAction to act on, using the
// given BeginStoryboardName to find a BeginStoryboard instance and use
// its Storyboard object reference.
private Storyboard GetStoryboard( FrameworkElement fe, FrameworkContentElement fce, INameScope nameScope )
{
if( BeginStoryboardName == null )
{
throw new InvalidOperationException(SR.Storyboard_BeginStoryboardNameRequired);
}
BeginStoryboard keyedBeginStoryboard = Storyboard.ResolveBeginStoryboardName( BeginStoryboardName, nameScope, fe, fce );
Storyboard storyboard = keyedBeginStoryboard.Storyboard;
if( storyboard == null )
{
throw new InvalidOperationException(SR.Format(SR.Storyboard_BeginStoryboardNoStoryboard, BeginStoryboardName));
}
return storyboard;
}
private string _beginStoryboardName = null;
}
}
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