參考資訊:
http://winapi.freetechsecrets.com/win32/
https://github.com/gammasoft71/Examples_Win32
http://masm32.com/board/index.php?topic=3584.0
一般在建立Windows視窗時,會註冊自定義的Class並且設定事件處理的副程式(callback),不過,目前範例使用的Class是系統預設的WC_DIALOG,因此,可以透過SetWindowLong()設定callback,這種替換callback的行為就稱為Subclass,意指為原本Class的Subclass,所以Subclass後,需要將原先callback的位址(SetWindowLong()的回傳值)保存下來,然後透過呼叫CallWindowProc()(傳入原先callback的位址),用來將處理控制權移交回原先視窗元件,所以當有多層Subclass的情形發生時,每次在處理事件時,記得判斷對應的Handle,如:在處理關閉事件時(WM_CLOSE),會先判斷目前的hWnd是否為當前的視窗hWnd,如果是當前視窗hWnd,才進行關閉的動作,避免關閉到其它視窗元件
main.asm
.386 .model flat,stdcall option casemap:none include c:\masm32\include\windows.inc include c:\masm32\include\kernel32.inc include c:\masm32\include\user32.inc includelib c:\masm32\lib\user32.lib includelib c:\masm32\lib\kernel32.lib .data szCaption db "main",0 hWin dd 0 hInstance dd 0 CommandLine dd 0 defWndProc dd 0 .code WndProc proc hWnd:HWND, uMsg:UINT, wParam:WPARAM, lParam:LPARAM .if uMsg == WM_CLOSE invoke DestroyWindow, hWnd xor eax, eax ret .elseif uMsg == WM_DESTROY invoke PostQuitMessage, 0 xor eax, eax ret .endif invoke CallWindowProc, defWndProc, hWnd, uMsg, wParam, lParam ret WndProc endp WinMain proc hInst:DWORD, hPrevInst:DWORD, CmdLine:DWORD, CmdShow:DWORD local msg:MSG invoke CreateWindowEx, WS_EX_LEFT, WC_DIALOG, offset szCaption, WS_OVERLAPPEDWINDOW or WS_VISIBLE, 0, 0, 300, 300, NULL, NULL, NULL, NULL mov hWin, eax invoke SetWindowLong, hWin, GWL_WNDPROC, WndProc mov defWndProc, eax @@: invoke GetMessage, addr msg, NULL, 0, 0 cmp eax, 0 je @f invoke DispatchMessage, addr msg jmp @b @@: mov eax, msg.wParam ret WinMain endp start: invoke GetModuleHandle, NULL mov hInstance, eax invoke GetCommandLine mov CommandLine, eax invoke WinMain, hInstance, NULL, CommandLine, SW_SHOWDEFAULT invoke ExitProcess, eax end start
Line 21~29:關閉視窗的順序為:主視窗收到WM_CLOSE事件時,呼叫DestroyWindow(),DestroyWindow()會自動將子視窗的相關資源也一併釋放掉(包含Resource描述的資源),系統接著會發送WM_DESTROY事件給主視窗,待主視窗收到WM_DESTROY事件時,呼叫PostQuitMessage()結束視窗,值得注意的地方是,SendMessage()是屬於Block方式呼叫(必須等待動作執行完畢才返回),而PostQuitMessage()則是Non-block方式呼叫
Line 31:將處理控制權移交給下一個視窗元件
完成