WPF通过代码更改的持续时间

Question

Hey all i am trying to change the duration of a DoubleAnimation with the following code:

 private Duration stay = new Duration(TimeSpan.FromSeconds(1));
    public Duration Stay
    {
        get { return stay; }

        set
        {
            if (stay == value) return;
            stay = value;
            OnPropertyChanged("Stay");
        }
    }

    protected virtual void OnPropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }

    public event PropertyChangedEventHandler PropertyChanged;

The error i get is:

Cannot freeze this Storyboard timeline tree for use across threads.

My XAML looks like this:

<EventTrigger RoutedEvent="Window.Loaded" SourceName="NotificationWindow">
   <BeginStoryboard x:Name="FadeInStoryBoard">
      <Storyboard>
         <DoubleAnimation Storyboard.TargetName="NotificationWindow" From="0.01" To="0.85" Storyboard.TargetProperty="Opacity" Duration="0:0:0.8">
         </DoubleAnimation>
         <DoubleAnimation Storyboard.TargetName="NotificationWindow" From="0.85" To="0" Storyboard.TargetProperty="Opacity" Duration="{Binding Path=Stay}" BeginTime="0:0:20" Name="boxDelay" x:Uid="boxDelay1">
         </DoubleAnimation>
      </Storyboard>
   </BeginStoryboard>
</EventTrigger>
   etc etc.....

Answer 1

Casting the object like that, even if found, won't work. See this example: http://msdn.microsoft.com/en-us/library/system.windows.frameworkelement.findname.aspx .

The end results will look something like:

DoubleAnimation theDA = null;
object objFound = stackPanel.FindName("dog");
if (objFound is DoubleAnimation)
{
    theDA = objFound as DoubleAnimation;
    ...
}