Fatal error c1189: # error: Windows. h already supported ded. MFC APPs must not # include

This situation is essentially for Windows. h. The header file is repeatedly referenced. The solution is to avoid referencing this header file if it can be referenced. If it must be referenced, or indirectly referenced by other header files, windows. h, so do not use stdafx. references in the H file can be solved in general.

Or you can use the followingCode:

Use the following code:

# Ifdef _ WINDOWS _
# UNDEF _ WINDOWS _
# Endif

Or # ifndef # define # endif

If not, change the header file location. Put # include "stdafx. H" before # include <windows. h>.