Creating a property trigger

So far we've used styles that have a collection of setters. A Style also has a Triggers collection property that provides a declarative way to make some property changes without a need for actual code. As such triggers are part of a style, they are naturally applied to more than one element. There are three types of triggers supported by WPF, and in this recipe we'll examine the simplest one - the property trigger.

Getting ready

Open the CH08.StyledCalculator project.

How to do it...

We'll add an effect when clicking a button in the calculator project using a property trigger:

1. We want to add a trigger to one of the styles we created in an earlier recipe. Open MainWindow.xaml and look for the style with the key numericStyle.

2. Add a Triggers property inside the style:

   <Style.Triggers>
   </Style.Triggers>

3. Add a property trigger inside the style (after the setters, before the closing style tag). The trigger will be invoked when the IsPressed property is changed to...