ActiveX DLL - Event Handler problem

[chrishui]

Hi. This is the first time that I post a message in this forum. Hope someone could give me a helping hand on this:


I have wrote a ActiveX DLL using VB6. And then I wrote a client program which use this ActiveX DLL

Here is the sample code for the client program

==========================
Option Explicit

Private WithEvents aa As BossCheckerOject.IQueryCmd
Private WithEvents bb As BossCheckerOject.IQueryCmd

Private Sub aa_DataArrival()
MsgBox "aaaa"
End Sub

Private Sub bb_DataArrival()
MsgBox "bbbbb"
End Sub

Private Sub Command1_Click()
Set aa = New BossCheckerOject.QueryCmd
Set bb = New BossCheckerOject.QueryCmd

aa.strBossIp = "127.0.0.1"
aa.strBossPort = "10000"
aa.m_intLocaleId = 2052
aa.SetRequestMsg "20050", "13922200525~6006~1"

aa.SendQuery
End Sub

Private Sub Form_Unload(Cancel As Integer)
Set aa = Nothing
Set bb = Nothing

End Sub
===================

The object I wrote "BossCheckerOject.QueryCmd" would fire a DataArrival event. I used the "aa" object to send a query out. I expected that I should received an event from the "aa" object. But then the event handler of "bb" handle the event.

Do you have any idea of what's going on?

Chris

[brucevde]

Probably a bug in your dll. I would suspect the new instance of the object has obsconded the control from the first instance.

[chrishui]

Thanks for your reply, brucevde.

I am not so sure if there is any bug in my original ActiveX DLL.

If you don't mind, could you give me some comments on my test program. I made a group project, which contains a dummy ActiveX DLL and a container program.

I created 3 objects in the container programs, and implements 3 event handlers in this container program. I only called the first object function once. But then all three event handlers got the events.... is there anything that I made it wrong?

Chris

[brucevde]

It is a bug in your Dll.

All instances of your class are using the same Form and thus the same timer. When the Timer_Timer event fires, all three class instances get the event and in turn all three raise their Data_Arrival events.

Create a new instance of the Form for each class - or add a new Timer to the form when the class gets initialized.

Private Sub Class_Initialize()
    Dim objForm As Form
    Set objForm = New Form1
    Load objForm
    Set myTimer = objForm.Timer1
End Sub
Private Sub Class_Terminate()
    Set myTimer = Nothing
End Sub

Also instead of using Form1.Timer.Enabled = False use myTimer.Enabled = False

[chrishui]

hi brucevde, I gotta say thank you again.
It fixed my problem now. Thank you so much.

What I was thinking is that the Active DLL is using the Apartment threading model, and so I expected that every instance of class is residing in its own apartment... but seems like the form is not in the apartment (which I thought it was)... Hehehe..

I really appreaciated that you pin-point my error.

Chris

[brucevde]

Apartment threading applies to two different programs using the same dll. Each program gets their own version of the dll and thus the Form.

[chrishui]

So, what you mean is:

for the sample program that I attached above, there is only thread (the container program), which has ONE apartment and all three objects or instances that I created are all resided in this apartment. Am I right?

And there will be another apartment only when there is another client progam (thread) that uses the same dll?


Chris

[brucevde]

Yes. That is how I understand it.