WPF application custom routed event

Question

I want to build something very straighforward like this:

<EventTrigger RoutedEvent="MyCustomEvent">
     <BeginStoryboard>
         <Storyboard>
             <DoubleAnimation Duration="00:00:00.1" Storyboard.TargetProperty="Opacity" To="1" />
         </Storyboard>
     </BeginStoryboard>
</EventTrigger>

So that I can call something like this in the code:

MyCustomEvent.trigger()

How can I do it, simple and fast, in C#, in a WPF application?

Answer 1

You have to use an extension method for a RoutedEvent , and use UIElement.RaiseEvent method.

Sample :

public static class EventHandlerExtension
{
    public static void TriggerThisEvent(this RoutedEvent routedEvt, FrameworkElement felem)
    {
        RoutedEventArgs args = new RoutedEventArgs(routedEvt, felem);
        felem.RaiseEvent(args);
    }
}

Usage

XAML

   <TextBox x:Name="Tbx" Text="type something here...">
        <TextBox.Triggers>
            <EventTrigger RoutedEvent="LostFocus">
                <BeginStoryboard>
                    <Storyboard>
                        <DoubleAnimation Duration="00:00:03" Storyboard.TargetProperty="Opacity" To="0" />
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </TextBox.Triggers>
    </TextBox>

CODE

    private void Btn1_Click(object sender, RoutedEventArgs e)
    {
        TextBox.LostFocusEvent.TriggerThisEvent(Tbx);
    }