[RESOLVED] DLL + ByRef parameters

[david.rougier]

Hi everyone,

I would like to know if it is possible to create routines with ByRef parameters in a class module offered by a DLL.

I have made a test by creating a routine with a ByRef boolean parameter in a class module from a VB6 DLL ActiveX project. Then, I called the routine passing a local boolean variable from a VB6 client project. But, the boolean variable is unchanged after the routine execution.

Thanks for your future help.

[RhinoBull]

Not sure how you did it so here is a quick example of how it's done:

'dll project
Option Explicit

Public Sub Test(ByRef a As String, ByRef b As Boolean)
    a = a & "b"
    b = Not b
End Sub

'standard project
Private Sub Command1_Click()
Dim oClass As myDll.Class1
Dim a As String
Dim b As Boolean

    a = "a"
    b = True
    
    Set oClass = New myDll.Class1
    oClass.Test a, b
    
    Debug.Print a; "; "; b    '<<< output is "ab; False"

End Sub

As you can see both parameters were changed.

[david.rougier]

I performed a new test and the ByRef mechanism works. I really don't know why my first test failed. Thanks for your help anyway.