[RESOLVED] Issue pssing data between VB 6.0 and .NET

[TysonLPrice]

I have a VB 6.0/.NET program combination that I'm trying to return data back to VB 6.0. I'm pretty sure I'm missing something simple.

This is the VB 6.0 program:

Private Sub cmdTestIt_Click()

Dim strX As String
strX = "1234"

Dim mImageMainNet As New ImageMainNet.Main
mImageMainNet.TestIt (strX)

MsgBox strX

End Sub

This is the .NET program:

<ComClass(Main.ClassID, Main.InterfaceID, Main.EventsID)>
Public Class Main

Public Sub TestIt(ByRef strX As String)
strX = "Test"
End Sub

End Class

I'm expecting the test "Test" to come back but it remains "1234". I know I'm hitting the .NET program via stepping through the code. I don't see what I'm missing. I thought ByRef would do it. Any suggestions?

[rasinc]

Have you tried changing ByRef to ByVal?

You could also use a Function instead of Sub and return strX from TestIt.

I haven't tested any of this but it is where I would start.

[Shaggy Hiker]

ByRef would be right. If you were to pass it ByVal, it should behave the way it is behaving. However, .NET and VB6 changed the default passing behavior. In .NET it is ByVal, which means that in VB6 it is ByRef (I don't remember, I just remember that the two languages swapped the default).

I've certainly never tried this, though.

[rasinc]

That's what I get for typing and reading too quickly and not thinking it through, sorry.

TysonLPrice, does TestIt see the "1234" in strX before strX is reset to "Test"?

[dday9]

I don't understand why your .NET method is a sub routine. It sounds like you expect to pass a value from your VB6 application, have your VB.NET application transform the value, and then the VB.NET application returns the transformed value. I don't have much experience with inter-application communication like this, but I'd expect something like this:

Public Function TestIt(ByVal strX As String) As String
    strX = "Test"
    Return strX
End Function

[TysonLPrice]

I tried a half a dozen times all day to try and post I made it a function and it works. Time out after time out....

Thanks to the responders