在父元素上的触发器中设置子元素的属性
我有一个用户控件，它由包含椭圆和视图框的画布组成。椭圆是背景，并且视图框在运行时用从另一个程序集加载的图形填充。我在为控件创建“热”行为时遇到问题，因此当鼠标悬停在椭圆上时，椭圆会改变颜色。
如果我在椭圆上放置触发器，则颜色会发生变化，但当鼠标移到视图框中的图形上时，颜色会变回来，因为视图框不是椭圆的子级。
根据我所读到的内容，应该可以通过父元素上的触发器来设置子元素的属性。但是，我无法让它发挥作用。我的代码如下所示：
<Viewbox Margin="5" >
<Viewbox.Resources>
<SolidColorBrush x:Key="HotColor" Color="Blue"/>
<SolidColorBrush x:Key="ColdColor" Color="Red"/>
<Style TargetType="Canvas" x:Key="BackgroundStyle">
<Setter Property="Ellipse.Fill" Value="{StaticResource ColdColor}"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Ellipse.Fill" Value="{StaticResource HotColor}"/>
</Trigger>
</Style.Triggers>
</Style>
</Viewbox.Resources>
<Canvas Width="44.000" Height="44.000" Style="{StaticResource BackgroundStyle}">
<Ellipse Width="44" Height="44"/>
<Viewbox Name="ButtonGraphics"/>
</Canvas>
</Viewbox>
结果是我的椭圆上根本没有颜色。有趣的是，如果我尝试设置 Ellipse.Opacity，它会起作用，但会影响椭圆和图形！所以看起来它被应用于画布，而不是椭圆？
I have a user cotrol which consists of a canvas that contains an ellipse and a viewbox. The ellipse is the background, and the viewbox is filled at runtime with graphics loaded from another assembly. I'm having problems creating a "hot" behavior for my control, so that the ellipse changes color when the mouse is over it.
If I put a trigger on the ellipse then the color changes, but it changes back when the mouse moves over the graphics in the viewbox because the viewbox is not a child of the ellipse.
From what I've read, it should be possible to set properties on child elments from a trigger on the parent element. However, I can't get this to work. My code looks like this:
<Viewbox Margin="5" >
<Viewbox.Resources>
<SolidColorBrush x:Key="HotColor" Color="Blue"/>
<SolidColorBrush x:Key="ColdColor" Color="Red"/>
<Style TargetType="Canvas" x:Key="BackgroundStyle">
<Setter Property="Ellipse.Fill" Value="{StaticResource ColdColor}"/>
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter Property="Ellipse.Fill" Value="{StaticResource HotColor}"/>
</Trigger>
</Style.Triggers>
</Style>
</Viewbox.Resources>
<Canvas Width="44.000" Height="44.000" Style="{StaticResource BackgroundStyle}">
<Ellipse Width="44" Height="44"/>
<Viewbox Name="ButtonGraphics"/>
</Canvas>
</Viewbox>
The result is that I get no color on my ellipse at all. Funny enough, if I try setting Ellipse.Opacity in stead, it works but affects both the ellipse and the graphics! So it looks like it is being applied to the canvas, and not the ellipse?
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当您将 Setter 与 ClassName.PropertyName 属性一起使用时，您并未在所有 ClassName 对象上设置 PropertyName。相反，您在样式对象类型（在您的例子中为 Canvas）上设置 ClassName.PropertyName。提供 ClassName.PropertyName 只是该属性的类限定路径。对于不透明度，Canvas.Opacity == Ellipse.Opacity == UIElement.Opacity。
现在，为了实现您想要的目的，在 ButtonGraphics ViewBox 上设置
IsHitTestVisible=False将阻止图形拦截鼠标事件。When you use a Setter with a ClassName.PropertyName property, you aren't setting PropertyName on all ClassName objects. Instead, you are setting ClassName.PropertyName on the styled object type (in your case Canvas). Giving a ClassName.PropertyName is just a class qualified path to that property. For Opacity, Canvas.Opacity == Ellipse.Opacity == UIElement.Opacity.
Now, in order to accomplish what you want, setting
IsHitTestVisible=Falseon the ButtonGraphics ViewBox will prevent the graphics from intercepting mouse events.只在 ViewBox 上设置
IsHitTestVisible=False怎么样？这会将其从命中测试中完全删除，并且鼠标事件将注册到您的 Ellipse。What about just setting
IsHitTestVisible=Falseon your ViewBox? This would remove it from hit-testing altogether and mouse events would register to your Ellipse.