Question:
I am creating an ActiveX DLL and I want to be able to fire events that can be cancelled similiarly to cancelling the Unload event for a form. however, I notice that even though an argument (passed byRef) can be included in the event declaration, there is not an explicit way to reference the argument in the ActiveX component after the event has fired—to then process the Cancel argument. See the included code:
ActiveX component code
Option Explicit
Public Event WillFire(Cancel As Boolean)
Public Sub myMethod(Cancel As Boolean)
RaiseEvent WillFire(False)
MsgBox "Event has Fired"
End Sub
Client code
Option Explicit
Private WithEvents myObject As CObject
Private Sub btnExample_Click()
Set myObject = New CObject
myObject.myMethod False
End Sub
Private Sub myObject_MethodHasFired()
MsgBox "Object Event has Fired"
End Sub
Private Sub myObject_MethodWillFire(Cancel As Boolean)
'if some condition exists then
' set cancel flag for the object method
Cancel = True
'endif
End Sub
My question is: How can I include a byRef argument in my Event Declaration and evaluate that same argument in the ActiveX component once the event has fired?
Answer:
You must pass a ByRef variable when you raise the event, because that is the variable that is passed to the client's event procedure:
Public Event WillFire(Cancel As Boolean)
Public Sub myMethod()
Dim b as boolean
RaiseEvent WillFire(b)
If b=true then
MsgBox "Event has not Fired"
Else
MsgBox "Event has Fired"
End If
End Sub
Try enclosing the b variable in two sets of parenthesis, ((b)), this passes the variable ByVal.
