Programming .NET 3.5

Events and Event Handlers

There are two ways to declare event handlers in Silverlight 2. The first is directly in the XAML:

<Button x:Name="myPushyButton" Content="Click Me Please" Height="30"
    Width="100" Grid.Column="1" Grid.Row="4" Click="myPushyButton_Click" 
/>

Figure 7-12. The completed Grid

When you declare a button in the XAML, IntelliSense is available to help you create the event handler name (as shown in Figure 7-13).

Figure 7-13. Inline event handler

If you use IntelliSense to wire the event handler, a skeleton event handler method is created in the code-behind (Page.xaml.cs):

private void myPushyButton_Click(object sender, Routed EventArgs e
{
   myPushyButton.Width *= 1.25;
   myPushyButton.Content = "Thanks, I needed that!";
}

The first thing to notice is that the name of the method is identical to that declared in the XAML.

The second is that this method follows the pattern of all .NET event handlers: it returns void and takes two parameters. The first is of type object and contains a reference to the object that raised the event. The second is of type EventArgs, or a type that derives from EventArgs (in this case, RoutedEventArgs). Also notice that nowhere in the code-behind do you see anything like this:

Button myPushyButton = GetTheButtonIDeclaredinTheXAML

Any object declared in the ...