BUG: Using Friend Function with Implements Does Not Work in P-Code (255630)


The information in this article applies to:

  • Microsoft Visual Basic Learning Edition for Windows 6.0
  • Microsoft Visual Basic Professional Edition for Windows 6.0
  • Microsoft Visual Basic Enterprise Edition for Windows 6.0
This article was previously published under Q255630

SYMPTOMS

When calling a friend procedure you get the following error:
Run-time error 97: Cannot call friend function on object which is not an instance of defining class.

CAUSE

This problem happens if the IMPLEMENTS statement is used in the object where the friend procedure is defined, and only if you compile your project to P-Code.

RESOLUTION

To avoid this problem you need to compile your project to Native Code.

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

Steps to Reproduce Behavior

  1. Start a new ActiveX DLL project. This project stores the base class. Class1 is created by default.
  2. Change the project name to MyBaseDll.
  3. Change the name of Class1 to BaseClass1.
  4. Add the following code to BaseClass1:
    Option Explicit

Public Function GetLong() as Long
End Function
Public Function GetLongB() as Long
End Function
  5. Save the project, and compile the DLL.
  6. Start a new ActiveX DLL project. Class1 is created by default.
  7. Change the project name to MyImplDll.
  8. From the Project menu, select References, select MyBaseDll, and then click OK.
  9. Change the name of Class1 to ImplClass1.
  10. Add the following code to ImplClass1. This code implements BaseClass1.
    Option Explicit

Implements MyBaseDll.BaseClass1

Friend Function BaseClass1_GetLong() As Long
    BaseClass1_GetLong = 7
End Function

Private Function BaseClass1_GetLongB() As Long
    BaseClass1_GetLongB = BaseClass1_GetLong()
End Function
  11. Add a new class to this project, and name it ImplClass2.
  12. Add the following code to ImplClass2:
    Option Explicit

Public Function GetLong() As Long
    Dim MyObj As New ImplClass1
    
    GetLong = MyObj.BaseClass1_GetLong()
End Function
  13. Save this project, and compile the DLL.
  14. Create a new Standard EXE project. This is the client to test the DLL. Form1 is created by default.
  15. Place a CommandButton on Form1.
  16. From the Project menu, select References, select MyBaseDll and MyImplDll, and then click OK.
  17. In Command1's click event, place the following code:
        Dim MyObjImpl As New MyImplDll.ImplClass1
    Dim MyObjImpl2 As New MyImplDll.ImplClass2
    Dim MyObjBase As New MyBaseDll.BaseClass1
    
    Set MyObjBase = MyObjImpl
    MsgBox MyObjBase.GetLong()
    MsgBox MyObjBase.GetLongB()
    MsgBox MyObjImpl2.GetLong()
  18. Save this project. Compile the project and close it.
  19. Run project1.exe and click on the Command button. Everything should work fine and you should see three message boxes, all of them displaying the value 7.
  20. Close project1.exe.
  21. Load the MyImplDll project.
  22. From the Project menu, select Project Properties. Select the Component tab and set Binary Compatibility to the compiled DLL.
  23. Then select the Compile tab and check the Compile to P-Code option.
  24. Close the Project Properties window and compile the DLL.
  25. Run project1.exe and click the Command button. You should see the first message box followed by an error message:
    Run-time error 97: Can not call friend function on object which is not an instance of defining class.
Modification Type:MajorLast Reviewed:5/13/2003
Keywords:kbBug KB255630
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