Mastering Visual Studio 2017

Property trigger

The most common trigger is the property trigger, which can be simply defined in XAML with a <Trigger> element. It triggers when a specific property on the owner control changes to match a specified value:

<Style TargetType="{x:Type CheckBox}"> 
  <Style.Triggers> 
     <Trigger Property="IsChecked" Value="True"> 
       <Setter Property="Background" Value="LightGreen"/> 
     </Trigger> 
     <Trigger Property="IsChecked" Value="False"> 
       <Setter Property="Background" Value="Red"/> 
     </Trigger> 
  </Style.Triggers> 
</Style> 

The preceding XAML code snippet creates a style for a checkbox control having two triggers associated with its property IsChecked. When the value is True, the background of the checkbox will be set to LightGreen, and when it is False