ClassWizard Links Only Types with DDX Support

WINDOWS        | WINDOWS NT

The information in this article applies to:

• The ClassWizard included with:

      - Microsoft Visual C++ for Windows, versions 1.5, 1.51, and 1.52
      - Microsoft Visual C++ 32-bit Edition, versions 2.0, 2.1, and 4.0
  

SYMPTOMS

By default, ClassWizard allows linking the edit controls of combo boxes only to member variables that are of type CString.

MORE INFORMATION

By design, ClassWizard allows links only to types for which dynamic data exchange (DDX) routines have been provided. Microsoft Foundation Classes (MFC) provides a DDX_FieldCBString() function to manage data transfer between the edit control of a combo box and a CString member variable, but not between combo boxes and other types (for example, there is no DDX_FieldCBInt). This is not a problem with ClassWizard; it is simply a matter of providing support for those DDX routines that are available.

If a particular routine that you would find useful does not already exist, you can create a custom routine. "MFC Technical Note #26" provides instructions on how to create custom DDX/DDV routines. Once a custom routine is provided, ClassWizard recognizes the type and allows the mapping to be made. This additional functionality may be useful when linking the edit controls of combo boxes to non-CString fields, such as those found in a database.