WPF触发器不为空 [英] WPF Trigger not null

问题描述

当属性不为空时，如何在WPF中触发动作？
当为空时，这是一个可行的解决方案：

How to trigger an action in WPF when the Property is not null? This is a working solution when is null:

<Style.Triggers>
    <DataTrigger Binding="{Binding}" Value="{x:Null}">

      <Setter Property="Background" Value="Yellow" />

    </DataTrigger>
</Style.Triggers>

我知道您无法扭转状况并做您需要的事情，但想知道

I know that you cant "turn around" the condition and do what you need, but want to know

推荐答案

不幸的是，你做不到。但这实际上不是必需的：您只需要在样式设置器中而不是在触发器中指定值不为null时的背景：

Unfortunately, you can't. But actually it's not necessary : you just need to specify the background for when the value is not null in the style setters, not in the trigger :

<Style.Setters>
    <!-- Background when value is not null -->
    <Setter Property="Background" Value="Blue" />
</Style.Setters>
<Style.Triggers>
    <DataTrigger Binding="{Binding}" Value="{x:Null}">

      <Setter Property="Background" Value="Yellow" />

    </DataTrigger>
</Style.Triggers>

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