PRB: Type Mismatch Error in Client After Modifying Server DLL

ID: Q190460

The information in this article applies to:

Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, version 6.0

SYMPTOMS

If an ActiveX DLL server has two classes and one class implements the other, running a compiled client project referencing the server will generate the following error after modifying and recompiling the server with binary compatibility:

Run-time error 13: Type mismatch

RESOLUTION

Reopen the client project and compile it again.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

Create the Server

Start a new ActiveX DLL project in Visual Basic. Class1 is created by default.

Select Project1 Properties from the Project menu and change the Project Name to "Server."

Select Add Class Module from the Project menu to add Class2 to the project.

Paste the following code in Class2:
```
      Public Sub Test()
      End Sub 
```

Paste the following code in Class1:


      Implements Class2

      Private Sub Class2_Test()
         MsgBox "Testing the Server"
      End Sub

Select Make Server.dll from the File menu to compile the project.

Save the Server project files.

Create the Client

Start a new Standard EXE project in Visual Basic 6.0. Form1 is created by default.

Select Project1 Properties from the Project menu, and change the Project Name to "Client."

Select References from the Project menu, and select "Server."

Paste the following code in Form1's code module:


      Private Sub Form_Load()
         Dim x As Server.Class2
         Set x = New Server.Class1
         TestMethod x
      End Sub

      Private Sub TestMethod (x As Server.Class2)
         x.Test
      End Sub

Select Make Client.exe from the File menu.

Test the Client with the Server

Run Client.exe outside the Visual Basic design environment. The program runs correctly.

Reopen the Server.dll project and add the following code to Class2:
```
      Public Sub Test2()
      End Sub
 
```

Add the following code to Class1:


      Private Sub Class2_Test2()
      End Sub

Select Server Properties from the Project menu, and select the Binary Compatibility option on the Component tab.

Select Make Server.dll from the File menu to compile the project. Overwrite the existing Server.dll.

Run Client.exe again. Note that the following error occurs:

Run-time error 13: Type mismatch

To resolve this, recompile the client, overwriting Client.exe. Run Client.exe and note that no error occurs.

Additional query words: kbdss kbDSupport kbVBp kbVBp600 kbCompiler

Keywords : kbCompiler kbVBp kbVBp600 kbGrpVB kbDSupport
Version : WINDOWS:6.0
Platform : WINDOWS
Issue type : kbprb