Question

I am trying to build a program that, once the button was click, every 5 second will perform the function (OnTimed).

Below is the code so far:

private void bntCapture_Click(object sender, RoutedEventArgs e)
{ 
    DispatcherTimer t1 = new DispatcherTimer();
    t1.Interval = TimeSpan.FromMilliseconds(5000);
    t1.IsEnabled = true;
    t1.Tick += new EventHandler(OnTimed);
    t1.Start();
}

void OnTimed(object sender, ElapsedEventArgs e)
{

    imgCapture.Source = imgVideo.Source;
    System.Threading.Thread.Sleep(1000);
    Helper.SaveImageCapture((BitmapSource)imgCapture.Source);
} 

When i run the code, it show the error:

“No overload for ‘method’ matches delegate ‘System.EventHandler’

Answer 1

The signature of the event-handler method isn’t compatible with the delegate type.

Subsribers to the DispatcherTimer.Tick event must be of the EventHandler delegate type, which is declared as:

public delegate void EventHandler(object sender, EventArgs e);

Try this instead:

void OnTimed(object sender, EventArgs e)
{
   ...
}