Troubleshooting Inherited Event Handlers in Visual Basic 2005
Visual Studio 2005
This topic lists common issues that arise with event handlers in inherited components.
Code in Event Handler Executes Twice for Every Call
An inherited event handler must not include aclause. The method in the base class is already associated with the event and will fire accordingly. Remove the Handles clause from the inherited method.
If the inherited method does not have a Handles keyword, verify that your code does not contain an extraor any additional methods that handle the same event.