Question

I have a button which slides out a menu using a storyboard by calling begin() on it like so

    private void ShareBtn_Click(object sender, RoutedEventArgs e)
    {
        SlideIn.Begin();
    }

On the grid which then slides out there are buttons.

Each button then slides the grid back and when that storyboard completes the action for the button then runs so like so,

    private void PictureBtn_Click(object sender, RoutedEventArgs e)
    {
        CertificateDisplay.SaveAsPicture();
    }

    private void FacebookBtn_Click(object sender, RoutedEventArgs e)
    {
        App.facebookSuccess = false;
        NavigationService.Navigate(new Uri("/FBLogin.xaml", UriKind.Relative));
    }

    private void SMSBtn_Click(object sender, RoutedEventArgs e)
    {
        SlideOut.Begin();
        SlideOut.Completed += delegate(object s, EventArgs se) { SlideOut_Completed(s, se, "Email"); };
    }

    private void EmailBtn_Click(object sender, RoutedEventArgs e)
    {
        SlideOut.Begin();
        SlideOut.Completed += delegate(object s, EventArgs se) { SlideOut_Completed(s, se, "Email"); };
    }

    void SlideOut_Completed(object sender, EventArgs e, String shareType)
    {
        switch (shareType)
        {
            case "Email":
               ...
            default:
               break;
        }
    }

The flaw I encountered if that I cannot remove the anonymous functions from the event stack.

I’ve managed to solve it by making shareType a common variable for all of the above functions and not using a anonymous delegate and then removing the “named” functions from the event stack when OnNavigatedFrom is called.

Is there a way to do this by still using those delegates because it looks neater?

Answer 1

One option is to remove it within the handler itself:

EventHandler handler = null;
handler = delegate(object s, EventArgs se) {
    SlideOut_Completed(s, se, "Email");
    SlideOut.Completed -= handler;
};
SlideOut.Completed += handler;
SlideOut.Begin();