參考資訊:
https://masm32.com/board/index.php
https://www.nasm.us/xdoc/2.13rc9/html/nasmdoc0.html
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
%include "c:\\nasmx\\inc\\nasmx.inc" %include "c:\\nasmx\\inc\\win32\\windows.inc" %include "c:\\nasmx\\inc\\win32\\user32.inc" %include "c:\\nasmx\\inc\\win32\\kernel32.inc" entry start section .data hWin dd 0 hInstance dd 0 defWndProc dd 0 CommandLine dd 0 szCaption declare(NASMX_TCHAR) NASMX_TEXT("main"),0 NASMX_ISTRUC msg, MSG NASMX_AT hwnd, NULL NASMX_AT message, NULL NASMX_AT wParam, NULL NASMX_AT lParam, NULL NASMX_AT time, NULL NASMX_ISTRUC pt, POINT NASMX_AT x, 0 NASMX_AT y, 0 NASMX_IENDSTRUC NASMX_IENDSTRUC section .text proc WndProc, dword hWnd, uint_t uMsg, dword wParam, dword lParam locals none switch dword [argv(.uMsg)] case dword WM_CLOSE invoke DestroyWindow, [argv(.hWnd)] break case dword WM_DESTROY invoke PostQuitMessage, 0 break default invoke CallWindowProc, [defWndProc], [argv(.hWnd)], [argv(.uMsg)], [argv(.wParam)], [argv(.lParam)] endswitch endproc proc WinMain, dword hInst, dword hPrevInst, dword CmdLine, dword CmdShow locals none invoke CreateWindowEx, WS_EX_LEFT, WC_DIALOG, szCaption, \ WS_OVERLAPPEDWINDOW | WS_VISIBLE, 0, 0, 300, 300, NULL, NULL, NULL, NULL mov [hWin], eax invoke SetWindowLong, [hWin], GWL_WNDPROC, WndProc mov [defWndProc], eax do invoke DispatchMessage, msg invoke GetMessage, msg, NULL, NULL, NULL while eax, !=, 0 mov eax, dword [msg + MSG.wParam] endproc proc start, dword argc, dword argv locals none invoke GetModuleHandle, NULL mov [hInstance], eax invoke GetCommandLine, NULL mov [CommandLine], eax invoke WinMain, [hInstance], NULL, [CommandLine], SW_SHOWNORMAL invoke ExitProcess, NULL endproc
Line 32~37: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 39:將處理控制權移交給下一個視窗元件
完成