PRB: Unable to Derive Classes from External Dependencies (167349)


The information in this article applies to:

  • Microsoft Visual C++, 32-bit Enterprise Edition 5.0
  • Microsoft Visual C++, 32-bit Enterprise Edition 6.0
  • Microsoft Visual C++, 32-bit Professional Edition 5.0
  • Microsoft Visual C++, 32-bit Professional Edition 6.0
  • Microsoft Visual C++, 32-bit Learning Edition 6.0
This article was previously published under Q167349

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.
Modification Type:MajorLast Reviewed:12/1/2003
Keywords:kbide kbprb KB167349
©2003 Microsoft Corporation. All rights reserved.