I use the following Interactivity Behavior to provide an unloading event to WPF UserControls. You can include the behavior in the UserControls XAML. So you can have the functionality without placing the logic it in every single UserControl.
XAML declaration:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
<i:Interaction.Behaviors>
<behaviors:UserControlSupportsUnloadingEventBehavior UserControlClosing="UserControlClosingHandler" />
</i:Interaction.Behaviors>
CodeBehind handler:
private void UserControlClosingHandler(object sender, EventArgs e)
{
// to unloading stuff here
}
Behavior Code:
/// <summary>
/// This behavior raises an event when the containing window of a <see cref="UserControl"/> is closing.
/// </summary>
public class UserControlSupportsUnloadingEventBehavior : System.Windows.Interactivity.Behavior<UserControl>
{
protected override void OnAttached()
{
AssociatedObject.Loaded += UserControlLoadedHandler;
}
protected override void OnDetaching()
{
AssociatedObject.Loaded -= UserControlLoadedHandler;
var window = Window.GetWindow(AssociatedObject);
if (window != null)
window.Closing -= WindowClosingHandler;
}
/// <summary>
/// Registers to the containing windows Closing event when the UserControl is loaded.
/// </summary>
private void UserControlLoadedHandler(object sender, RoutedEventArgs e)
{
var window = Window.GetWindow(AssociatedObject);
if (window == null)
throw new Exception(
"The UserControl {0} is not contained within a Window. The UserControlSupportsUnloadingEventBehavior cannot be used."
.FormatWith(AssociatedObject.GetType().Name));
window.Closing += WindowClosingHandler;
}
/// <summary>
/// The containing window is closing, raise the UserControlClosing event.
/// </summary>
private void WindowClosingHandler(object sender, CancelEventArgs e)
{
OnUserControlClosing();
}
/// <summary>
/// This event will be raised when the containing window of the associated <see cref="UserControl"/> is closing.
/// </summary>
public event EventHandler UserControlClosing;
protected virtual void OnUserControlClosing()
{
var handler = UserControlClosing;
if (handler != null)
handler(this, EventArgs.Empty);
}
}