Q189740: BUG: Class Builder Does Not Handle Base Classes Properly

Article: Q189740
Product(s): Microsoft Visual Basic for Windows
Version(s): 
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
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SYMPTOMS
========

The Class Builder Utility incorrectly displays derived classes and base class
properties.

RESOLUTION
==========

Before creating a derived class, select the appropriate base class in the Class
pane. In the Class Module Builder dialog, select the base class in the Based On
list and check the box for "This Class is a Top Level Object."

Alternatively, create the derived class directly with code, without using the
class builder utility.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. We are researching this bug and will post new
information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Add the following classes using the Class Builder Utility:

   - Add a class called Person; with two properties Age and FirstName.

   - Add a class called Employee based on Person.

   - Add a class called Customer based on Person.

  At this point you will find that Customer is actually subordinate to Employee
  instead of Person; this would seem to be wrong because we indicated that
  Customer was supposed to be based on Person. Instead, Customer was based on
  the Employee class because that was the selected class in the Classes pane.

2. Delete the Customer class.

3. Select the Person class in the Classes pane.

4. Add a class called Customer based on Person.

  This creates a perceived hierarchy of classes in the Class pane, but Employee
  and Customer were created as components of Person, rather than derivatives.
  Examine the properties of each class to see that Person has both Customer and
  Employee as additional properties. Customer has Employee as a property and
  Employee has no properties.

To workaround this problem, do the following:

1. Delete the Employee and Customer classes.

2. Select the Person class and create a new class. Choose Person in the Based On
  list and check the box for "This Class is a Top Level Object."

  When this new class is created, view its properties and note that it has the
  same properties as Person. Also note that the new class is at the same
  "level" in the Class pane as the Base class. This is correct; a derived class
  is not a subordinate or child of the base class.

REFERENCES
==========

Books Online for Microsoft Visual Basic, version 5.0

Books Online for Microsoft Visual Basic, version 6.0

Additional query words: kbDSupport kbdss kbVBp500bug kbWizard kbVBp kbVBp600bug

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600
Issue type        : kbbug
Solution Type     : kbpending

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