在 ListBoxItem 的 ControlTemplate 中的 VisualState 中设置背景 属性？

Question

我想将 Background 属性 设置为 LinearGradientBrush 但它似乎有很多限制，original code 看起来像这样：

<VisualState x:Name="Selected">
    <Storyboard>
      <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border"
                                    Storyboard.TargetProperty="(Panel.Background).
        (SolidColorBrush.Color)">
        <EasingColorKeyFrame KeyTime="0"
                             Value="{StaticResource SelectedBackgroundColor}" />
      </ColorAnimationUsingKeyFrames>
    </Storyboard>
</VisualState>

我认为这可能有效：

<VisualState x:Name="Selected">
    <Storyboard>
        <ColorAnimationUsingKeyFrames Storyboard.TargetName="Border" Storyboard.TargetProperty="(Panel.Background).(LinearGradientBrush)">
            <EasingColorKeyFrame KeyTime="0">
                <EasingColorKeyFrame.Value>
                    <GradientStopCollection>
                        <GradientStop/>
                        <GradientStop/>
                    </GradientStopCollection>
                </EasingColorKeyFrame.Value>
            </EasingColorKeyFrame>
        </ColorAnimationUsingKeyFrames>
    </Storyboard>
</VisualState>

但事实并非如此：

The specified value cannot be assigned. The following type was expected: "Color".

Property 'Value' does not support values of type 'GradientStopCollection'.

Answer 1

这应该有效：

<VisualState x:Name="Pressed">
    <Storyboard>
        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background">
            <DiscreteObjectKeyFrame KeyTime="0">
                <DiscreteObjectKeyFrame.Value>
                    <LinearGradientBrush>
                        <GradientStop Color="Red"/>
                        <GradientStop Color="Green" Offset="1"/>
                    </LinearGradientBrush>
                </DiscreteObjectKeyFrame.Value>
            </DiscreteObjectKeyFrame>
        </ObjectAnimationUsingKeyFrames>
    </Storyboard>
</VisualState>