在Jeffrey的Error Show程序作者自定義了一段宏
#define chHANDLE_DLGMSG(hWnd, message, fn) \
case (message): return (SetDlgMsgResult(hWnd, uMsg, \
HANDLE_##message((hWnd), (wParam), (lParam), (fn))))
HANDLE_##message((hWnd), (wParam), (lParam), (fn))是借用了windows.h里面的
#define HANDLE_MSG(hwnd, message, fn)
case (message): return HANDLE_##message((hwnd), (wParam), (lParam), (fn))
如果message是ＷＭ＿ＣＲＥＡＴ的話，這個(gè)應(yīng)該是
HANDLE_WM_CREATE((hwnd), (wParam), (lParam), (Cls_OnCreate))
＃define HANDLE_WM_CREATE(hwnd, wParam, lParam, fn) \
((fn)((hwnd), (LPCREATESTRUCT)(lParam)) ? 0L : (LRESULT)-1L)
那么宏展開為：return Cls_OnCreate(hwnd, (LPCREATESTRUCT)(lParam) )? 0L : (LRESULT)-1L;
但是在對(duì)話框消息處理中,對(duì)話框過程函數(shù)應(yīng)該在處理了消息的情況下返回TRUE，如果沒有處理，則返回FALSE。如果對(duì)話框過程返回了FALSE，那么對(duì)話框管理器為這條消息準(zhǔn)備默認(rèn)的對(duì)話操作。如果對(duì)話框處理了一個(gè)需要特定返回值的消息，則對(duì)話框的返回值應(yīng)該被設(shè)置為調(diào)用SetWindowLong后的返回值,這些特殊消息有:
? WM_CHARTOITEM
? WM_COMPAREITEM
? WM_CTLCOLORBTN
? WM_CTLCOLORDLG
? WM_CTLCOLOREDIT
? WM_CTLCOLORLISTBOX
? WM_CTLCOLORSCROLLBAR
? WM_CTLCOLORSTATIC
? WM_INITDIALOG
? WM_QUERYDRAGICON
? WM_VKEYTOITEM
所以在處理WM_INITDIALOG 時(shí),我們不能單純的調(diào)用消息分流器.
而在處理ＷＭ＿ＣＯＭＭＡＮＤ中，從windowsx.h可以看到:
/* void Cls_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify) */
#define HANDLE_WM_COMMAND(hwnd, wParam, lParam, fn) \
((fn)((hwnd), (int)(LOWORD(wParam)), (HWND)(lParam), (UINT)HIWORD(wParam)), 0L)
void Cls_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify)
Cls_OnCommand由于是個(gè)void型的函數(shù)，是沒有返回值的，因此windows默認(rèn)這種消息處理過程必須返回一個(gè)0值，而返回0值不就表示我們的消息過程不處理這個(gè)消息,這是矛盾的,如果直接使用HANDLE_WM_COMMAND(hwnd, wParam, lParam, Dlg_OnCommand) ;按鈕會(huì)沒有反應(yīng),關(guān)閉也不行/所以可以使用使用下面的宏解決
#define SetDlgMsgResult(hwnd, msg, result) (( \
(msg) == WM_CTLCOLORMSGBOX || \
(msg) == WM_CTLCOLOREDIT || \
(msg) == WM_CTLCOLORLISTBOX || \
(msg) == WM_CTLCOLORBTN || \
(msg) == WM_CTLCOLORDLG || \
(msg) == WM_CTLCOLORSCROLLBAR || \
(msg) == WM_CTLCOLORSTATIC || \
(msg) == WM_COMPAREITEM || \
(msg) == WM_VKEYTOITEM || \
(msg) == WM_CHARTOITEM || \
(msg) == WM_QUERYDRAGICON || \
(msg) == WM_INITDIALOG \
) ? (BOOL)(result) : (SetWindowLong((hwnd), DWL_MSGRESULT, (LPARAM)(LRESULT)(result)), TRUE))
#define chHANDLE_DLGMSG(hWnd, message, fn) \
case (message): return (SetDlgMsgResult(hWnd, uMsg, \
HANDLE_##message((hWnd), (wParam), (lParam), (fn))))
從這兩個(gè)宏可以得到,如果是特殊消息的話那么返回默認(rèn)0,并設(shè)置說明消息處理,如果WM_COMMAND的話,那么返回SetWindowLong((hwnd), DWL_MSGRESULT, (LPARAM)(LRESULT)(result)), TRUE),一般為TRUE表明已經(jīng)處理