Using triggers in WPF

A trigger enables you to change property values when certain conditions are satisfied. It can also enable you to take actions based on property values by allowing you to dynamically change the appearance and/or the behavior of your control without writing additional codes in the code behind classes.

In WPF, the triggers are usually defined in a style or in the root of an element, which are applied to that specific control. There are five types of triggers:

• Property trigger
• Multi trigger
• Data trigger
• Multidata trigger
• Event trigger

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> 
     &lt...