The type or namespace name 'EventHandler' could not be found

c#, xamarin

Solution

EventHandler is defined in System namespace:

   using System;

Problem

I am using C# with Xamarin, when using EventHandler, I got this error: ``` The type or namespace name 'EventHandler' could not be found(are you missing a using dirrective or an assembly reference?)(CS0246) ``` Here is my code: ``` using Emgu.CV; using Emgu.CV.UI; using Emgu.CV.Structure; using System.Drawing; using System.Windows.Forms; namespace Emgu_Hello_World { public class EmptyClass { public static void Main(string[] args) { ImageViewer viewer = new ImageViewer (); Capture capture = new Capture (); Application.Idle += new EventHandler (delegate(object sender, EventArgs e) { viewer.Image = capture.QueryFrame (); }); viewer.ShowDialog (); } } } ``` What should I referenced to?

Original source