Question

我想重复使用storyboad中定义的resourcedictionnary并在 App.xaml

中引用

<Storyboard x:Key="ShowWindowStoryboard">
    <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)"
                                   >
        <EasingDoubleKeyFrame KeyTime="0:0:0.3"
                              Value="1" />
    </DoubleAnimationUsingKeyFrames>
    <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)"
                                   >
        <EasingDoubleKeyFrame KeyTime="0:0:0.3"
                              Value="1" />
    </DoubleAnimationUsingKeyFrames>
    <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)"
                                   >
        <EasingDoubleKeyFrame KeyTime="0:0:0.3"
                              Value="1" />
    </DoubleAnimationUsingKeyFrames>
</Storyboard>

这里是给出异常的代码

Storyboard sb = (FindResource("ShowWindowStoryboard") as Storyboard).Clone();



        DoubleAnimation da0 = sb.Children[0] as DoubleAnimation;
         /* Exception here da0 is null*/
        Storyboard.SetTarget(da0, uc); 

        DoubleAnimation da1 = sb.Children[1] as DoubleAnimation;
        Storyboard.SetTarget(da1, uc);

        DoubleAnimation da2 = sb.Children[2] as DoubleAnimation;
        Storyboard.SetTarget(da2, uc);
        sb.Begin();

我还按预期检查了sb.children.Count == 3。

Answer 1

您必须将TransformGroup添加到uc控件的RenderTransform中。我将向图像添加TransformGroup。这同样适用于您的控件uc。

<强> XAML

<Image Source="untitled.bmp" Name="ImgDemo">
    <Image.RenderTransform>
        <TransformGroup>
            <ScaleTransform/>    
        </TransformGroup>
    </Image.RenderTransform>
</Image>

如果你必须在代码中添加TransformGroup，你可以在调用Story.Begin之前使用以下内容：

TransformGroup transformGroup = new TransformGroup();
transformGroup.Children.Add(new ScaleTransform(1,1));
uc.RenderTransform = transformGroup;

您的Storyboard.TargetProperty应该反映您希望应用故事板的对象的签名。这就是你面临异常的原因。此外，您可能希望稍微更改Storyboard以实际查看对象的更改。像，

<Storyboard x:Key="ShowWindowStoryboard">
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)"
                               >
    <EasingDoubleKeyFrame KeyTime="0:0:0.3"
                          Value="0.5" />
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)"
                               >
    <EasingDoubleKeyFrame KeyTime="0:0:0.3"
                          Value="0.5" />
</DoubleAnimationUsingKeyFrames>
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)"
                               >
    <EasingDoubleKeyFrame KeyTime="0:0:0.3"
                          Value="0.5" />
</DoubleAnimationUsingKeyFrames>

请注意，值已更改，以便动画显而易见。最后，我确实看到你调用故事板后面的代码没有使用正确的转换。所以你可能想考虑使用以下内容，

 Storyboard sb = (FindResource("ShowWindowStoryboard") as Storyboard).Clone();

    DoubleAnimationUsingKeyFrames da0 = sb.Children[0] as DoubleAnimationUsingKeyFrames;
        Storyboard.SetTarget(da0, ImgDemo);

        DoubleAnimationUsingKeyFrames da1 = sb.Children[1] as DoubleAnimationUsingKeyFrames;
        Storyboard.SetTarget(da1, ImgDemo);

        DoubleAnimationUsingKeyFrames da2 = sb.Children[2] as DoubleAnimationUsingKeyFrames;
        Storyboard.SetTarget(da2, ImgDemo);
        sb.Begin();

祝你好运！

如何在WPF中使用故事板

1 个答案: