ON_COMMAND(IDM_ABOUT, OnAbout)
ON_COMMAND(IDM_FILENEW, OnFileNew)

　　它是如何实现的IDM_ABOUT和OnAbout的关联的呢？这要用到几个宏。

#define DECLARE_MESSAGE_MAP() \
private: \
static const AFX_MSGMAP_ENTRY _messageEntries[]; \

protected: \
static AFX_DATA const AFX_MSGMAP messageMap; \
virtual const AFX_MSGMAP* GetMessageMap() const; \

#define BEGIN_MESSAGE_MAP(theClass, baseClass) \
const AFX_MSGMAP* theClass::GetMessageMap() const \
{ return &theClass::messageMap; } \
AFX_COMDAT AFX_DATADEF const AFX_MSGMAP theClass::messageMap = \
{ &baseClass::messageMap, &theClass::_messageEntries[0] }; \
AFX_COMDAT const AFX_MSGMAP_ENTRY theClass::_messageEntries[] = \
{ \

#define ON_COMMAND(id, memberFxn) \
{ WM_COMMAND, 0, (WORD)id, (WORD)id, AfxSig_vv, (AFX_PMSG)memberFxn },

#define END_MESSAGE_MAP() \
{0, 0, 0, 0, AfxSig_end, (AFX_PMSG)0 } \
}; \
#define DECLARE_MESSAGE_MAP() \
private: \
static const AFX_MSGMAP_ENTRY _messageEntries[]; \
protected: \
static AFX_DATA const AFX_MSGMAP messageMap; \
virtual const AFX_MSGMAP* GetMessageMap() const; \

#define BEGIN_MESSAGE_MAP(theClass, baseClass) \
const AFX_MSGMAP* theClass::GetMessageMap() const \
{ return &theClass::messageMap; } \
AFX_COMDAT AFX_DATADEF const AFX_MSGMAP theClass::messageMap = \
{ &baseClass::messageMap, &theClass::_messageEntries[0] }; \
AFX_COMDAT const AFX_MSGMAP_ENTRY theClass::_messageEntries[] = \
{ \

#define ON_COMMAND(id, memberFxn) \
{ WM_COMMAND, 0, (WORD)id, (WORD)id, AfxSig_vv, (AFX_PMSG)memberFxn },

#define END_MESSAGE_MAP() \
{0, 0, 0, 0, AfxSig_end, (AFX_PMSG)0 } \
}; \

　　嘿嘿，就这么几个宏，就构造出一个消息数组来。