MFC 中 CreateEx() 函数

BOOL CtestDialogApp::InitInstance()
{
     //自己用 CreateEx() 创建主窗口,需要自己注册窗口类
    CWnd* pWnd = new CWnd();//要想接收消息，则需要新建一个类继承 CWnd，像 CMyMainWnd
    //CWnd* pWnd = new CMyMainWnd();
    WNDCLASS wc = { 0 };
    wc.style = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS;
    wc.lpfnWndProc = ::DefWindowProc;
    wc.hbrBackground = (HBRUSH)GetStockObject(DKGRAY_BRUSH);
    wc.hCursor = (HCURSOR)::LoadCursor(NULL, MAKEINTRESOURCE(IDC_ARROW));//加载系统的标准的光标
    //wc.hIcon=...
    wc.lpszMenuName = MAKEINTRESOURCE(IDR_MENU1);// 也可以用 (LPCTSTR)IDR_MENU1;
    wc.lpszClassName = _T("myWindow");
    RegisterClass(&wc);

    m_pMainWnd = pWnd; // 必不可少
    pWnd->CreateEx(0, wc.lpszClassName, _T("xxx窗口名"), WS_VISIBLE|WS_OVERLAPPEDWINDOW, 20, 20, 600, 400, NULL, NULL);
    return TRUE; // 必不可少
}

// WNDCLASS
typedef struct  _WNDCLASS { 
    UINT       style; 
    WNDPROC    lpfnWndProc; 
    int        cbClsExtra; 
    int        cbWndExtra; 
    HINSTANCE  hInstance; 
    HICON      hIcon; 
    HCURSOR    hCursor; 
    HBRUSH     hbrBackground; 
    LPCTSTR    lpszMenuName; 
    LPCTSTR    lpszClassName; 
} WNDCLASS, *PWNDCLASS; 

//
MSG
The MSG structure contains message information from a thread‘s message queue. 

typedef struct tagMSG {
  HWND   hwnd; 
  UINT   message; 
  WPARAM wParam; 
  LPARAM lParam; 
  DWORD  time; 
  POINT  pt; 
} MSG, *PMSG; 

//Members
hwnd ：Handle to the window whose window procedure receives the message. 
message ：Specifies the message identifier. Applications can only use the low word; the high word is reserved by the system. 
wParam ：Specifies additional information about the message. The exact meaning depends on the value of the message member. 
lParam ：Specifies additional information about the message. The exact meaning depends on the value of the message member. 
time ：Specifies the time at which the message was posted. 
pt ：Specifies the cursor position, in screen coordinates, when the message was posted.