Setting a LinearGradientBrush instead of a solid color to a storyboard.targetProperty in a VisualState

Question

I'm wondering how I can set a Storyboard.TargetProperty to a LinearGradientBrush instead of a solid color. I'm new to VisualStates so please let me know if I'm not given enough information for my question. Mostly I just want to set a Gradient instead of a solid color and can't figure out how. Thanks for any help. I'm working from an example I found at http://msdn.microsoft.com/en-us/library/ms753328.aspx.

 <VisualState x:Name="Disabled">
    <Storyboard>
        <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background).
                  (GradientBrush.GradientStops)[1].(GradientStop.Color)"
                                            Storyboard.TargetName="Border">
                <EasingColorKeyFrame KeyTime="0"
                                     Value="{StaticResource DisabledControlDarkColor}" />
              </ColorAnimationUsingKeyFrames>
              <ColorAnimationUsingKeyFrames
                  Storyboard.TargetProperty="(TextBlock.Foreground).(SolidColorBrush.Color)"
                                            Storyboard.TargetName="Border">
                <EasingColorKeyFrame KeyTime="0"
                                     Value="{StaticResource DisabledForegroundColor}" />
              </ColorAnimationUsingKeyFrames>
              <ColorAnimationUsingKeyFrames Storyboard.TargetProperty="(Border.BorderBrush).
                  (GradientBrush.GradientStops)[1].(GradientStop.Color)"
                                            Storyboard.TargetName="Border">
                <EasingColorKeyFrame KeyTime="0"
                                     Value="{StaticResource DisabledBorderDarkColor}" />
              </ColorAnimationUsingKeyFrames>
            </Storyboard>
          </VisualState>

score 10 · Accepted Answer · answered May 17 '11 at 00:15

The code you pasted animates certain stops in the existing gradient which is applied as the Background property. If you just want to replace the whole Background with a new brush (which happens to be a LinearGradientBrush) you can do so using a ObjectAnimationUsingKeyFrames.

The documentation even gives this example:

      <Storyboard>

        <!-- ObjectAnimationUsingKeyFrames is used to animate properties that take
             an object as a value. This animation lasts for 4 seconds using 3 KeyFrames which
             swap different brush objects at regular intervals, making the background of the Page
             change. -->
        <ObjectAnimationUsingKeyFrames
          Storyboard.TargetProperty="Background"
          Duration="0:0:4" RepeatBehavior="Forever">
        <ObjectAnimationUsingKeyFrames.KeyFrames>

          <!-- Note: Only discrete interpolation (DiscreteObjectKeyFrame) is available for 
          use with ObjectAnimationUsingKeyFrames which merely swaps objects according to
          a specified timeline. Other types of interpolation are too problematic to apply
          to objects.  -->

          <!-- Using a DiscreteObjectKeyFrame, the Page Background suddenly changes 
               to a LinearGradientBrush after the first second of the animation. -->
          <DiscreteObjectKeyFrame KeyTime="0:0:1">
            <DiscreteObjectKeyFrame.Value>
              <LinearGradientBrush>
                <LinearGradientBrush.GradientStops>
                  <GradientStop Color="Yellow" Offset="0.0" />
                  <GradientStop Color="Orange" Offset="0.5" />
                  <GradientStop Color="Red" Offset="1.0" />
                </LinearGradientBrush.GradientStops>
              </LinearGradientBrush>
            </DiscreteObjectKeyFrame.Value>
          </DiscreteObjectKeyFrame>

          <!-- ... -->

Dang, this is really obvious now that you say it! Thanks! – Terco May 17 '11 at 00:36 — Terco, May 17 '11 at 00:36

Setting a LinearGradientBrush instead of a solid color to a storyboard.targetProperty in a VisualState

1 Answers1