MFC注册窗口类

MFC带有注册("register")字样的函数不少呀！主要有下面几个：

AfxDeferRegisterClassBOOL AFXAPI AfxEndDeferRegisterClass(LONG fToRegister)LPCTSTR AFXAPI AfxRegisterWndClass(UINT nClassStyle,HCURSOR hCursor, HBRUSH hbrBackground, HICON hIcon)BOOL AFXAPI AfxRegisterClass(WNDCLASS* lpWndClass)

首先，AfxDeferRegisterClass与AfxEndDeferRegisterClass是一回事。看看下面那个宏就知道了。

#define AfxDeferRegisterClass(fClass) AfxEndDeferRegisterClass(fClass)

AfxEndDeferRegisterClass参数只有一个，注册的是系统预定义类。

BOOL AFXAPI AfxEndDeferRegisterClass(LONG fToRegister){...if (fToRegister & AFX_WND_REG){// Child windows - no brush, no icon, safest default class styleswndcls.style = CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;wndcls.lpszClassName = _afxWnd;if (AfxRegisterClass(&wndcls))fRegisteredClasses |= AFX_WND_REG;}if (fToRegister & AFX_WNDMDIFRAME_REG){// MDI Frame window (also used for splitter window)wndcls.style = CS_DBLCLKS;wndcls.hbrBackground = NULL;if (_AfxRegisterWithIcon(&wndcls, _afxWndMDIFrame, AFX_IDI_STD_MDIFRAME))fRegisteredClasses |= AFX_WNDMDIFRAME_REG;}if (fToRegister & AFX_WNDFRAMEORVIEW_REG){// SDI Frame or MDI Child windows or views - normal colorswndcls.style = CS_DBLCLKS | CS_HREDRAW | CS_VREDRAW;wndcls.hbrBackground = (HBRUSH) (COLOR_WINDOW + 1);if (_AfxRegisterWithIcon(&wndcls, _afxWndFrameOrView, AFX_IDI_STD_FRAME))fRegisteredClasses |= AFX_WNDFRAMEORVIEW_REG;}...}

AfxRegisterWndClass利用WNDCLASS里头的五个字段，构造一个类名，并注册它。

LPCTSTR AFXAPI AfxRegisterWndClass(UINT nClassStyle,HCURSOR hCursor, HBRUSH hbrBackground, HICON hIcon){...HINSTANCE hInst = AfxGetInstanceHandle();if (hCursor == NULL && hbrBackground == NULL && hIcon == NULL){ATL_CRT_ERRORCHECK_SPRINTF(_sntprintf_s(lpszName, _AFX_TEMP_CLASS_NAME_SIZE, _AFX_TEMP_CLASS_NAME_SIZE - 1, _T("Afx:%p:%x"), hInst, nClassStyle));}else{ATL_CRT_ERRORCHECK_SPRINTF(_sntprintf_s(lpszName, _AFX_TEMP_CLASS_NAME_SIZE, _AFX_TEMP_CLASS_NAME_SIZE - 1, _T("Afx:%p:%x:%p:%p:%p"), hInst, nClassStyle,hCursor, hbrBackground, hIcon));}WNDCLASS wndcls;if (::AfxCtxGetClassInfo(hInst, lpszName, &wndcls)){ASSERT(wndcls.style == nClassStyle);return lpszName;}wndcls.style = nClassStyle;wndcls.lpfnWndProc = DefWindowProc;wndcls.cbClsExtra = wndcls.cbWndExtra = 0;wndcls.hInstance = hInst;wndcls.hIcon = hIcon;wndcls.hCursor = hCursor;wndcls.hbrBackground = hbrBackground;wndcls.lpszMenuName = NULL;wndcls.lpszClassName = lpszName;if (!AfxRegisterClass(&wndcls))AfxThrowResourceException();return lpszName;}

AfxRegisterClass是最终调用的函数了，它又调用API函数RegisterClass。