BeginStoryboard.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / System / Windows / Media / Animation / BeginStoryboard.cs / 1305600 / BeginStoryboard.cs
                        
                        
                            /****************************************************************************\ 
*
* File: BeginStoryboard.cs
*
* This object includes a Storyboard reference.  When triggered, the Storyboard 
*  is started.
* 
* Copyright (C) by Microsoft Corporation.  All rights reserved. 
*
\***************************************************************************/ 
using System.ComponentModel;            // DefaultValueAttribute
using System.Diagnostics;               // Debug.Assert
using System.Windows;                   // SR.Get
using System.Windows.Documents;         // TableTemplate 
using System.Windows.Markup;     // IAddChild
 
namespace System.Windows.Media.Animation 
{
///  
/// BeginStoryboard will call begin on its Storyboard reference when
///  it is triggered.
/// 
[RuntimeNameProperty("Name")] // Enables INameScope.FindName to find BeginStoryboard objects. 
[ContentProperty("Storyboard")] // Enables  child without explicit  tag.
public sealed class BeginStoryboard : TriggerAction 
{ 

    ///  
    ///     Creates an instance of the BeginStoryboard object.
    /// 
    public BeginStoryboard()
        : base() 
    {
    } 
 
    /// 
    ///     DependencyProperty to back the Storyboard property 
    /// 
    public static readonly DependencyProperty StoryboardProperty =
                DependencyProperty.Register( "Storyboard", typeof(Storyboard), typeof(BeginStoryboard) );
 

    ///  
    ///     The Storyboard object that this action is associated with.  This 
    /// must be specified before Invoke is called.
    ///  
    [DefaultValue(null)]
    public Storyboard Storyboard
    {
        get 
        {
            return GetValue(StoryboardProperty) as Storyboard; 
        } 
        set
        { 
            ThrowIfSealed();

            SetValue( StoryboardProperty, value );
        } 
    }
 
    ///  
    ///     Specify the hand-off behavior to use when starting the animation
    /// clocks in this storyboard 
    /// 
    [DefaultValue(HandoffBehavior.SnapshotAndReplace)]
    public HandoffBehavior HandoffBehavior
    { 
        get
        { 
            return _handoffBehavior; 
        }
        set 
        {
            ThrowIfSealed();

            if(HandoffBehaviorEnum.IsDefined(value)) 
            {
                _handoffBehavior = value; 
            } 
            else
            { 
                throw new ArgumentException(SR.Get(SRID.Storyboard_UnrecognizedHandoffBehavior));
            }
        }
    } 

    ///  
    ///     The name to use for referencing this Storyboard.  This named is used 
    /// by a control action such as pause and resume.  Defaults to null, which
    /// means this storyboard is not going to be interactively controlled. 
    /// 
    // Null == no interactive control == "Fire and Forget"
    [DefaultValue(null)]
    public string Name 
    {
        get 
        { 
            return _name;
        } 
        set
        {
            ThrowIfSealed();
 
            if(value != null && !System.Windows.Markup.NameValidationHelper.IsValidIdentifierName(value))
            { 
                // Duplicate the error string thrown from DependencyObject.SetValueValidateParams 
                throw new ArgumentException(SR.Get(SRID.InvalidPropertyValue, value, "Name"));
            } 

            // Null is OK - it's to remove whatever name was previously set.
            _name = value;
        } 
    }
 
    private void ThrowIfSealed() 
    {
        if (IsSealed) 
        {
            throw new InvalidOperationException(SR.Get(SRID.CannotChangeAfterSealed, "BeginStoryboard"));
        }
    } 

    // Bug #1329664 workaround to make beta 2 
    // Remove thread affinity when sealed, but before doing that, snapshot the 
    //  current Storyboard value and remove *its* thread affinity too.
    internal override void Seal() 
    {
        if( !IsSealed )
        {
            // Gets our Storyboard value.  This value may have come from a 
            //  ResourceReferenceExpression or might have been a deferred
            //  reference that has since been realized. 
            Storyboard snapshot = GetValue(StoryboardProperty) as Storyboard; 

            if( snapshot == null ) 
            {
                // This is the same error thrown by Begin if the Storyboard
                //  property couldn't be resolved at Begin time.  Since we're
                //  not allowing changes after this point, lack of resolution 
                //  here means the same thing.
                throw new InvalidOperationException(SR.Get(SRID.Storyboard_StoryboardReferenceRequired)); 
            } 

            // We're planning to break our thread affinity - we also need to 
            //  make sure the Storyboard can also be used accross threads.
            if(!snapshot.CanFreeze)
            {
                throw new InvalidOperationException(SR.Get(SRID.Storyboard_UnableToFreeze)); 
            }
            if(!snapshot.IsFrozen) 
            { 
                snapshot.Freeze();
            } 

            // Promote that snapshot into a local value.  This is a no-op if it
            //  was a deferred reference or local Storyboard, but if it came from a
            //  ResourceReferenceExpression it will replace the Expression object 
            //  with a snapshot of its current value.
            Storyboard = snapshot; 
        } 
        else
        { 
            ; // base.Seal() will throw exception for us if already sealed.
        }

        base.Seal(); 

        // Now we can break our thread affinity 
        DetachFromDispatcher(); 
    }
 
    /// 
    ///     Called when it's time to execute this storyboard action
    /// 
 
    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." ); 

        INameScope nameScope = null; 
        if( targetStyle != null )
        {
            nameScope = targetStyle;
        } 
        else
        { 
            Debug.Assert( frameworkTemplate != null ); 
            nameScope = frameworkTemplate;
        } 


        Begin( (fe != null ) ? (DependencyObject)fe : (DependencyObject)fce, nameScope, layer );
    } 

    internal sealed override void Invoke( FrameworkElement fe ) 
    { 
        Debug.Assert( fe != null, "Invoke needs an object as starting point");
 
        Begin( fe, null, Storyboard.Layers.ElementEventTrigger );
    }

    private void Begin( DependencyObject targetObject, INameScope nameScope, Int64 layer ) 
    {
        if( Storyboard == null ) 
        { 
            throw new InvalidOperationException(SR.Get(SRID.Storyboard_StoryboardReferenceRequired));
        } 

        if( Name != null )
        {
            Storyboard.BeginCommon(targetObject, nameScope, _handoffBehavior, true /* == is controllable */, layer ); 
        }
        else 
        { 
            Storyboard.BeginCommon(targetObject, nameScope, _handoffBehavior, false /* == not controllable */, layer );
        } 
    }

    private HandoffBehavior _handoffBehavior = HandoffBehavior.SnapshotAndReplace;
    private string _name = null; 
}
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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BeginStoryboard.cs source code in C# .NET

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