SPWorkflowEventReceiver class

This is the base class for Workflow Event Receivers. This class is never instantiated.

Namespace:  Microsoft.SharePoint.Workflow
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)

public class SPWorkflowEventReceiver : SPEventReceiverBase, 

A workflow event receiver class must derive from this class and override the methods for the event types it wants to handle.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.