Troubleshooting Inherited Event Handlers in Visual Basic 2005 

This topic lists common issues that arise with event handlers in inherited components.

Procedures

Code in Event Handler Executes Twice for Every Call

• An inherited event handler must not include a Handles clause. The method in the base class is already associated with the event and will fire accordingly. Remove the Handles clause from the inherited method.

  ' INCORRECT
  Protected Overrides Sub Button1_Click( _
      ByVal sender As System.Object, _
      ByVal e As System.EventArgs) _
      Handles Button1.Click
  
      ' The Handles clause will cause all code
      ' in this block to be executed twice.
  End Sub
  

• If the inherited method does not have a Handles keyword, verify that your code does not contain an extra AddHandler Statement or any additional methods that handle the same event.

See Also

Tasks

How to: Write Event Handlers

Concepts

Events and Event Handlers
How to: Handle Events in Visual Basic

Other Resources

Events in Visual Basic