PRB: VB4 16-Bit Clients Cannot Early-Bind to VB5 .EXE Servers

MORE INFORMATION

Step-by-Step Example

1. Start 32-bit Visual Basic 4.0.
2. Remove Form1 and insert a module (Module1) and a class module (Class1).
3. Add the procedure Sub Main() to Module1.
4. Set Class1's Name property to CServer, Instancing property to 2- Creatable MultiUse and Public property to True.
5. On the Tools menu, click Options. In the Options dialog box, select the Project tab. Change Project Name to Server32, set StartMode to OLE Server, and enter an Application Description of "32-Bit Visual Basic Server."
6. Paste the following code into the General Declarations section of the CServer (formerly Class1) class module:

          Private mName As String
   
          Private Sub Class_Initialize()
             mName = "Default name"
          End Sub
          Public Property Get sName() As String
             sName = mName
          End Property
          Public Property Let sName(vNewValue As String)
             mName = vNewValue
          End Property
   
   						

7. Save the BAS module as Server32M.bas, the class module as Server32C.cls, and the project as Server32.vbp, and then compile the project as Server32.exe.
8. Exit Visual Basic 4.0 32-bit.
9. Start 16-bit Visual Basic 4.0.
10. On the Tools menu, click References and then check 32-Bit Visual Basic Server. You may have to use the Browse button to add Server32.exe to the references list.
11. Add the controls listed in the table below to your form (Form1). Change the name property of these controls to the value listed in the Updated Name column and change the caption property of those controls to the value listed in the Updated Caption column.

           Control Type   Default Name   Updated Name  Updated Caption
           -----------------------------------------------------------------
           TextBox        Text1          txtEarly
           TextBox        Text2          txtLate
           Label          Label1                       lblEarly
           Label          Label2                       lblLate
           CommandButton  Command1       cmdEarly      Change Early's Name
           CommandButton  Command2       cmdLate       Change Late's Name
    
    						

12. Change Form1's Name property to frmTest.
13. Paste the following code into the General Declarations section of frmTest (formerly Form1):

           Dim LateObj As Object
           Dim EarlyObj As New Server32.CServer
    
           Private Sub cmdLate_Click()
              On Error GoTo LateErrHandler:
              With LateObj
                 .sName = txtLate
                 lblLate = .sName
              End With
              Exit Sub
           LateErrHandler:
              MsgBox Err.Number & "  " & Err.Description
           End Sub
           Private Sub cmdEarly_Click()
              On Error GoTo EarlyErrHandler:
              With EarlyObj
                 .sName = txtEarly
                 lblEarly = .sName
              End With
              Exit Sub
           EarlyErrHandler:
              MsgBox Err.Number & "  " & Err.Description
           End Sub
           Private Sub Form_Load()
              On Error GoTo LoadErrHandler:
              Set LateObj = CreateObject("server32.CServer")
              lblEarly.Caption = EarlyObj.sName
              Exit Sub
           LoadErrHandler:
              MsgBox Err.Number & "  " & Err.Description
           End Sub
    
    						

14. Test and then save the form as Client16.frm and the project as Client16.vbp.
15. Compile the project as Client16.exe and then exit Visual Basic 4.0 16-bit. Run Client16.exe and verify that both the early and late buttons work correctly.
16. Copy Server32.exe to Server32B.exe (the backup copy) and copy the Server32 project files to a new (backup) directory.
17. Open the original Server32 project in 32-bit Visual Basic 4.0.
18. Select the Options menu item from the Tools menu, and on the resulting Options dialog, select the Project tab. Under Compatible OLE Server, use the ellipsis button ("...") to select Server32B.exe (the backup copy of Server32.exe).
19. Recompile the project, making sure it over-writes the original copy of Server32.exe, and then exit Visual Basic 4.0 32-bit.
20. Run Client16.exe. It should still work if you have followed these steps correctly.
21. Using Visual Basic 5.0 or 6.0, recompile the Server32 project into Server32.exe and make sure it over-writes the original copy of Server32.exe.
22. Run Client16.exe.