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Compiler Error CS0070 

Error Message

The event 'event' can only appear on the left hand side of += or -= (except when used from within the type 'type')

Outside of the class it is defined in, an event can only add or subtract references. For more information, see Events (C# Programming Guide).

The following sample generates CS0070:

// CS0070.cs
using System;
public delegate void EventHandler();

public class A
   public event EventHandler Click;

   public static void OnClick()
      EventHandler eh;
      A a = new A();
      eh = a.Click;

   public static void Main()

public class B
   public int Foo ()
      EventHandler eh = new EventHandler(A.OnClick);
      A a = new A();
      eh = a.Click;   // CS0070
      // try the following line instead
      // a.Click += eh;
      return 1;

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