关于C1189: #error : WINDOWS.H already included. 异常

关于C1189: #error :WINDOWS.H already included. 错误在一个文件中包含了#includeafx.h编译整个工程出

关于C1189: #error : WINDOWS.H already included. 错误
在一个文件中包含了#include   <afx.h>

编译整个工程出错如下:

c:/msvstudio6/common/msdev98/../../VC98/MFC/include\afxv_w32.h(14)   :   fatal   error   C1189:   #error   :     WINDOWS.H   already   included.     MFC   apps   must   not   #include   <windows.h>

请问怎么回事呢?

[解决办法]
#include <afxwin.h>