WTL中消息映射用BEGIN_MSG_MAP等宏来实现,以下为BEGIN_MSG_MAP宏的定义:#define BEGIN_MSG_MAP(theClass) \
public: \
BOOL ProcessWindowMessage(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, LRESULT& lResult, DWORD dwMsgMapID = 0) \
{ \
BOOL bHandled = TRUE; \
(hWnd); \
(uMsg); \
(wParam); \
(lParam); \
(lResult); \
(bHandled); \
switch(dwMsgMapID) \
{ \
case 0:定义了ProcessWindowMessage函数的实现,其中 (hWnd); \
(uMsg); \
(wParam); \
(lParam); \
(lResult); \
(bHandled); \这几句的意图是???