wpf - 更改 DragEnter 的背景

Question

我想在触发 DragEnter 事件时更改框架元素的背景，并在触发 DragLeave 事件时恢复其背景。此外，我希望以一种风格应用它。

这是我目前拥有的:

<EventTrigger RoutedEvent="Button.DragEnter">
            <BeginStoryboard x:Name="DragHoverStoryboard">
                <Storyboard>
                    <DoubleAnimation Storyboard.Target="??????????"
                                     Storyboard.TargetProperty="Background"
                                     Duration="0:0:0"
                                     To="{DynamicResource HoverBrush}" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
        <EventTrigger RoutedEvent="Button.DragLeave">
            <StopStoryboard BeginStoryboardName="DragHoverStoryboard" />
        </EventTrigger>
        <EventTrigger RoutedEvent="Button.Drop">
            <StopStoryboard BeginStoryboardName="DragHoverStoryboard" />
        </EventTrigger>

这里的问题是我无法通过名称应用目标，因为这种样式可以应用于任何 FrameworkElement。如何将目标应用于样式附加到的元素？

Answer 1

Storyboard.Target 不是问题，只是将其排除在外。但是，您需要更改动画的其余部分。要为颜色设置动画，请使用 ColorAnimation 而不是 DoubleAnimation。此外，属性“Background”不包含颜色，而是包含画笔，因此请为属性“Background.Color”设置动画。这是一个工作示例:

<Style TargetType="Button">
    <Setter Property="Background" Value="Red"/>
    <Style.Triggers>
        <EventTrigger RoutedEvent="Button.DragEnter">
            <BeginStoryboard x:Name="DragHoverStoryboard">
                <Storyboard>
                    <ColorAnimation Storyboard.TargetProperty="Background.Color" 
                                    Duration="0:0:0" To="Green" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
        <EventTrigger RoutedEvent="Button.DragLeave">
            <BeginStoryboard>
                <Storyboard>
                    <ColorAnimation Storyboard.TargetProperty="Background.Color" 
                                    Duration="0:0:0" To="Red" />
                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </Style.Triggers>
</Style>