EventProcPrefix Property
You can use the EventProcPrefix property to get the prefix portion of an event procedure name. Read/write String.
expression.EventProcPrefix
expression Required. An expression that returns one of the objects in the Applies To list.
Remarks
For example, if you have a command button with an event procedure named Details_Click, the EventProcPrefix property returns the string "Details".
The EventProcPrefix property setting is a string expression.
This property is available only by using a macro or Visual Basic and is read-only in all views.
Microsoft Access adds the prefix portion of an event procedure name to the event name with an underscore character (_).