Q167349: PRB: Unable to Derive Classes from External Dependencies

Article: Q167349
Product(s): Microsoft C Compiler
Version(s): winnt:5.0,6.0
Operating System(s): 
Keyword(s): kbide kbVC500 kbVC600 kbGrpDSTools
Last Modified: 17-JUL-2001

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The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0 
- Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

When you try to create a new class derived from a generic class using the New
Class Wizard, you might get the following error message:

  The New Class Wizard could not find the appropriate header file(s) to include
  for the base class(es) <base class name>. If you choose to derive from
  the class(es) anyway, you may need to manually add the appropriate header
  file(s) to <derived class file>.

CAUSE
=====

The New Class Wizard can only derive from classes explicitly included in the
project. Classes that are only in the External Dependencies folder are not
considered part of the project. That is, if the base class' header file, where
the base class is declared, is not included in the project, the wizard cannot
add the header to the derived class' header file.

RESOLUTION
==========

To resolve the problem, you can do one of the following:

- Close the message box and derive the class anyway. Add the base class header
  file manually to the derived class' header file.

-or-

- Add the base class header file to the project. On the Project menu, click Add
  To Project, and then select Files. Browse for the base class header file,
  then click OK. After doing this, you should be able to derive the class
  without any warning messages.

Once the new class has been derived, you may remove the base class file from the
project, and it will appear in the External Dependencies folder on the next
build.

STATUS
======

This behavior is by design.

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

The following procedures can be used to reproduce the problem.

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

1. Use the AppWizard to generate a generic MFC application.

2. Create a header file named CTestClass.h in which you declare a base class.
  Make sure CTestClass.h is not added to the project. Delete it from FileView
  if necessary.

3. Derive a class from CTestClass. by clicking New Class on the Insert menu. In
  "Class type:" choose "Generic Class". Name the derived class
  CTestClassDerived. Enter CTestClass as the class name in the Derived From
  edit box.

4. Click OK to save the derivation and exit the New Class dialog box.

5. You should get the error message box mentioned previously before the dialog
  box is closed.

Additional query words: member methods wizards VwbIss

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Keywords          : kbide kbVC500 kbVC600 kbGrpDSTools 
Technology        : kbVCsearch kbAudDeveloper kbVC500 kbVC600 kbVC32bitSearch kbVC500Search
Version           : winnt:5.0,6.0
Issue type        : kbprb

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