Attached Behavior handling an Attached Event in WPF

Question

I googled regarding this question but couldn't gather any information and I was wondering if it is possible for an attached behavior to handle an attached event??

I've an event declared in a class and a behavior that I am attaching to a TextBox control, the event will be raised when a button is clicked. I added the handler for this event in my behavior and wrote the logic in the event handler, but it is not executed. So, I was wondering if it is possible for an attached behavior to handle an attached event or not?

class ResetInputEventClass
{
    public static readonly RoutedEvent ResetInputEvent =  EventManager.RegisterRoutedEvent("ResetInput",
      RoutingStrategy.Bubble,
      typeof(RoutedEventHandler),
      typeof(ResetInputEventClass));

    public static void AddResetInputEventHandler(DependencyObject d, RoutedEventHandler handler)
    {
        UIElement uie = d as UIElement;
        if (uie == null)
        {
            return;
        }
        uie.AddHandler(ResetInputEventClass.ResetInputEvent, handler);
    }

    public static void RemoveResetInputEventHandler(DependencyObject d, RoutedEventHandler handler)
    {
        UIElement uie = d as UIElement;
        if (uie == null)
        {
            return;
        }
        uie.RemoveHandler(ResetInputEventClass.ResetInputEvent, handler);
    }
}

That is my Event class and this is how I am handling it in the behavior

public class MyBehavior : Behavior<TextBoxBase>
{
    public MyBehavior()
    {
        // Insert code required on object creation below this point.

    }        

    protected override void OnAttached()
    {
        base.OnAttached();
        // Insert code that you would want run when the Behavior is attached to an object.
        ResetInputEventClass.AddResetInputEventHandler(AssociatedObject, OnResetInputEvent);
    }

    protected override void OnDetaching()
    {
        base.OnDetaching();
        // Insert code that you would want run when the Behavior is removed from an object.
        ResetInputEventClass.RemoveResetInputEventHandler(AssociatedObject, OnResetInputEvent);
    }

    private void OnResetInputEvent(Object o, RoutedEventArgs e)
    {
        //Logic
    }
}

Here is my XAML Code:

<Grid x:Name="LayoutRoot">
    <StackPanel>
        <TextBox Margin="5" Text="Bye" TextWrapping="Wrap" Width="150">
            <i:Interaction.Behaviors>
                <local:MyBehavior/>
            </i:Interaction.Behaviors>
        </TextBox>
        <TextBox Margin="5" Text="Bye" TextWrapping="Wrap" Width="150">
            <i:Interaction.Behaviors>
                <local:MyBehavior/>
            </i:Interaction.Behaviors>
        </TextBox>
        <Button Name="MyButton" Content="Save" Width="50" Height="25" Click="MyButton_Click"/>
    </StackPanel>
</Grid>

and I am raising the event in the click event of my button

private void MyButton_Click(object sender, RoutedEventArgs e)
{
    RoutedEventArgs eventArgs = new RoutedEventArgs(ResetInputEventClass.ResetInputEvent,e.OriginalSource);
    RaiseEvent(eventArgs);
}

Answer 1

Your problem is simple. The textbox is registered for the event, but the parent of the textbox is raising it. Thus the handler is never called. You can change the event to make it a Tunneling event instead of Bubbling. Or you can get a handle on your textbox (give it a name and reference in code behind). And have it raise the event.

<Grid x:Name="LayoutRoot">
<StackPanel>
<TextBox Margin="5" x:Name="byeTextBox" Text="Bye" TextWrapping="Wrap" Width="150">
                    <i:Interaction.Behaviors>
                        <local:MyBehavior/>
                    </i:Interaction.Behaviors>
                </TextBox>
<Button Name="MyButton" Content="Save" Width="50" Height="25" Click="MyButton_Click"/>
</StackPanel>
</Grid>

Your code-behind should then look like this

private void MyButton_Click(object sender, RoutedEventArgs e)
        {
            RoutedEventArgs eventArgs = new RoutedEventArgs(ResetInputEventClass.ResetInputEvent,e.OriginalSource);
            byeTextBox.RaiseEvent(eventArgs);
        }

and that should fix your problem.