14 Windows编程——SetWindowLong

使用默认窗口处理函数，源码

  1 #include<Windows.h>
  2 #include<Windowsx.h>
  3 
  4 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  5 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  6 
  7 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
  8 {
  9     WNDCLASS WndClass;
 10     TCHAR* ClassName = TEXT("MyClass");
 11     HWND hwnd;
 12     MSG msg;
 13     HBRUSH hBrush = CreateSolidBrush(RGB(200, 200, 200));
 14 
 15     WndClass.cbClsExtra = 0;
 16     WndClass.cbWndExtra = 0;
 17     WndClass.hbrBackground = hBrush;
 18     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
 19     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
 20     WndClass.hInstance = hInst;
 21     WndClass.lpfnWndProc = WindProc;
 22     WndClass.lpszClassName = ClassName;
 23     WndClass.lpszMenuName = NULL;
 24     WndClass.style = CS_VREDRAW | CS_HREDRAW;
 25 
 26     if (!RegisterClass(&WndClass))
 27     {
 28         MessageBox(NULL, TEXT("Gegister Class Fail!!"), TEXT("error"), MB_OK);
 29         return 0;
 30     }
 31 
 32     //CreateWindow返回之前，会发送WM_CREATE消息
 33     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 300, NULL, NULL, hInst, NULL);
 34     if (hwnd == NULL)
 35     {
 36         MessageBox(NULL, TEXT("Create Window Fail!!"), TEXT("error"), MB_OK);
 37         return 0;
 38     }
 39     ShowWindow(hwnd, nShow);
 40     UpdateWindow(hwnd);
 41 
 42     while (GetMessage(&msg, NULL, 0, 0))
 43     {
 44         TranslateMessage(&msg);
 45         DispatchMessage(&msg);
 46     }
 47 
 48     return 0;
 49 }
 50 
 51 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 52 {
 53     PAINTSTRUCT pt;
 54     static int cx, cy;
 55     HDC hdc;
 56     HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 240));
 57     switch (message)
 58     {
 59     case WM_CREATE:
 60         //SetWindowLong(hwnd, GWL_WNDPROC, (LONG)MyProc);
 61         return 0;
 62     case WM_SIZE:
 63         cx = LOWORD(lParam);
 64         cy = HIWORD(lParam);
 65         return 0;
 66     case WM_PAINT:
 67         hdc = BeginPaint(hwnd, &pt);
 68         HBRUSH hBrush = CreateSolidBrush(RGB(0,255,0));
 69         SelectObject(hdc, hBrush);
 70         Rectangle(hdc, 0, 0, cx/2, cy/2);
 71         DeleteObject(hBrush);
 72         EndPaint(hwnd, &pt);
 73         return 0;
 74     case WM_DESTROY:
 75         PostQuitMessage(0);
 76         return 0;
 77     default:
 78         break;
 79     }
 80 
 81     return DefWindowProc(hwnd, message, wParam, lParam);
 82 }
 83 
 84 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 85 {
 86     PAINTSTRUCT ps;
 87     HDC hdc;
 88     static int cx, cy;
 89 
 90     switch (message)
 91     {
 92     case WM_SIZE:
 93         cx = LOWORD(lParam);
 94         cy = HIWORD(lParam);
 95         return 0;
 96     case WM_PAINT:
 97         hdc = BeginPaint(hwnd, &ps);
 98     
 99         EndPaint(hwnd, &ps);
100         return 0;
101     default:
102         break;
103     }
104     return DefWindowProc(hwnd, message, wParam, lParam);
105 }

View Code

运行结果(只能使用Alt+F4关闭)：

使用SetWindowLong替换窗户口处理函数，源码

  1 #include<Windows.h>
  2 #include<Windowsx.h>
  3 
  4 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  5 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  6 
  7 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
  8 {
  9     WNDCLASS WndClass;
 10     TCHAR* ClassName = TEXT("MyClass");
 11     HWND hwnd;
 12     MSG msg;
 13     HBRUSH hBrush = CreateSolidBrush(RGB(200, 200, 200));
 14 
 15     WndClass.cbClsExtra = 0;
 16     WndClass.cbWndExtra = 0;
 17     WndClass.hbrBackground = hBrush;
 18     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
 19     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
 20     WndClass.hInstance = hInst;
 21     WndClass.lpfnWndProc = WindProc;
 22     WndClass.lpszClassName = ClassName;
 23     WndClass.lpszMenuName = NULL;
 24     WndClass.style = CS_VREDRAW | CS_HREDRAW;
 25 
 26     if (!RegisterClass(&WndClass))
 27     {
 28         MessageBox(NULL, TEXT("Gegister Class Fail!!"), TEXT("error"), MB_OK);
 29         return 0;
 30     }
 31 
 32     //CreateWindow返回之前，会发送WM_CREATE消息
 33     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 300, NULL, NULL, hInst, NULL);
 34     if (hwnd == NULL)
 35     {
 36         MessageBox(NULL, TEXT("Create Window Fail!!"), TEXT("error"), MB_OK);
 37         return 0;
 38     }
 39     ShowWindow(hwnd, nShow);
 40     UpdateWindow(hwnd);
 41 
 42     while (GetMessage(&msg, NULL, 0, 0))
 43     {
 44         TranslateMessage(&msg);
 45         DispatchMessage(&msg);
 46     }
 47 
 48     return 0;
 49 }
 50 
 51 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 52 {
 53     PAINTSTRUCT pt;
 54     static int cx, cy;
 55     HDC hdc;
 56     HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 240));
 57     switch (message)
 58     {
 59     case WM_CREATE:
 60         SetWindowLong(hwnd, GWL_WNDPROC, (LONG)MyProc);
 61         return 0;
 62     case WM_SIZE:
 63         cx = LOWORD(lParam);
 64         cy = HIWORD(lParam);
 65         return 0;
 66     case WM_PAINT:
 67         hdc = BeginPaint(hwnd, &pt);
 68         HBRUSH hBrush = CreateSolidBrush(RGB(0,255,0));
 69         SelectObject(hdc, hBrush);
 70         Rectangle(hdc, 0, 0, cx/2, cy/2);
 71         DeleteObject(hBrush);
 72         EndPaint(hwnd, &pt);
 73         return 0;
 74     case WM_DESTROY:
 75         PostQuitMessage(0);
 76         return 0;
 77     default:
 78         break;
 79     }
 80 
 81     return DefWindowProc(hwnd, message, wParam, lParam);
 82 }
 83 
 84 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 85 {
 86     PAINTSTRUCT ps;
 87     HDC hdc;
 88     static int cx, cy;
 89 
 90     switch (message)
 91     {
 92     case WM_SIZE:
 93         cx = LOWORD(lParam);
 94         cy = HIWORD(lParam);
 95         return 0;
 96     case WM_PAINT:
 97         hdc = BeginPaint(hwnd, &ps);
 98         HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 0));
 99         SelectObject(hdc, hBrush);
100         Rectangle(hdc, cx / 2, cy / 2, cx, cy);
101         DeleteObject(hBrush);
102         EndPaint(hwnd, &ps);
103         return 0;
104     default:
105         break;
106     }
107     return DefWindowProc(hwnd, message, wParam, lParam);
108 }

View Code

运行结果：

使用SetWindowLong接管原来窗口处理函数后，把WM_PAINT消息先在MyProc处理一次，然后交给原来的窗口处理函数再处理一次。但是发现并没有绘制出原来窗口处理函数绘制的图形

  1 #include<Windows.h>
  2 #include<Windowsx.h>
  3 
  4 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  5 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  6 
  7 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
  8 {
  9     WNDCLASS WndClass;
 10     TCHAR* ClassName = TEXT("MyClass");
 11     HWND hwnd;
 12     MSG msg;
 13     HBRUSH hBrush = CreateSolidBrush(RGB(200, 200, 200));
 14 
 15     WndClass.cbClsExtra = 0;
 16     WndClass.cbWndExtra = 0;
 17     WndClass.hbrBackground = hBrush;
 18     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
 19     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
 20     WndClass.hInstance = hInst;
 21     WndClass.lpfnWndProc = WindProc;
 22     WndClass.lpszClassName = ClassName;
 23     WndClass.lpszMenuName = NULL;
 24     WndClass.style = CS_VREDRAW | CS_HREDRAW;
 25 
 26     if (!RegisterClass(&WndClass))
 27     {
 28         MessageBox(NULL, TEXT("Gegister Class Fail!!"), TEXT("error"), MB_OK);
 29         return 0;
 30     }
 31 
 32     //CreateWindow返回之前，会发送WM_CREATE消息
 33     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 300, NULL, NULL, hInst, NULL);
 34     if (hwnd == NULL)
 35     {
 36         MessageBox(NULL, TEXT("Create Window Fail!!"), TEXT("error"), MB_OK);
 37         return 0;
 38     }
 39     ShowWindow(hwnd, nShow);
 40     UpdateWindow(hwnd);
 41 
 42     while (GetMessage(&msg, NULL, 0, 0))
 43     {
 44         TranslateMessage(&msg);
 45         DispatchMessage(&msg);
 46     }
 47 
 48     return 0;
 49 }
 50 
 51 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 52 {
 53     PAINTSTRUCT pt;
 54     static int cx, cy;
 55     HDC hdc;
 56     HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 240));
 57     switch (message)
 58     {
 59     case WM_CREATE:
 60         SetWindowLong(hwnd, GWL_WNDPROC, (LONG)MyProc);
 61         return 0;
 62     case WM_SIZE:
 63         cx = LOWORD(lParam);
 64         cy = HIWORD(lParam);
 65         return 0;
 66     case WM_PAINT:
 67         hdc = BeginPaint(hwnd, &pt);
 68         HBRUSH hBrush = CreateSolidBrush(RGB(0,255,0));
 69         SelectObject(hdc, hBrush);
 70         Rectangle(hdc, 0, 0, cx/2, cy/2);
 71         DeleteObject(hBrush);
 72         EndPaint(hwnd, &pt);
 73         return 0;
 74     case WM_DESTROY:
 75         PostQuitMessage(0);
 76         return 0;
 77     default:
 78         break;
 79     }
 80 
 81     return DefWindowProc(hwnd, message, wParam, lParam);
 82 }
 83 
 84 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 85 {
 86     PAINTSTRUCT ps;
 87     HDC hdc;
 88     static int cx, cy;
 89 
 90     switch (message)
 91     {
 92     case WM_SIZE:
 93         cx = LOWORD(lParam);
 94         cy = HIWORD(lParam);
 95         return 0;
 96     case WM_PAINT:
 97         hdc = BeginPaint(hwnd, &ps);
 98         HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 0));
 99         SelectObject(hdc, hBrush);
100         Rectangle(hdc, cx / 2, cy / 2, cx, cy);
101         DeleteObject(hBrush);
102         EndPaint(hwnd, &ps);
103         //return 0;
104         break;
105     default:
106         break;
107     }
108     return WindProc(hwnd, message, wParam, lParam);
109 }

View Code

经调试，发现WindProc函数中WM_PAINT消息，cx=0,cy=0。绘制了，只不过绘制的矩形坐标时（ 0 0 0 0），修改如下

方式① 源码

  1 #include<Windows.h>
  2 #include<Windowsx.h>
  3 
  4 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  5 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  6 
  7 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
  8 {
  9     WNDCLASS WndClass;
 10     TCHAR* ClassName = TEXT("MyClass");
 11     HWND hwnd;
 12     MSG msg;
 13     HBRUSH hBrush = CreateSolidBrush(RGB(200, 200, 200));
 14 
 15     WndClass.cbClsExtra = 0;
 16     WndClass.cbWndExtra = 0;
 17     WndClass.hbrBackground = hBrush;
 18     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
 19     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
 20     WndClass.hInstance = hInst;
 21     WndClass.lpfnWndProc = WindProc;
 22     WndClass.lpszClassName = ClassName;
 23     WndClass.lpszMenuName = NULL;
 24     WndClass.style = CS_VREDRAW | CS_HREDRAW;
 25 
 26     if (!RegisterClass(&WndClass))
 27     {
 28         MessageBox(NULL, TEXT("Gegister Class Fail!!"), TEXT("error"), MB_OK);
 29         return 0;
 30     }
 31 
 32     //CreateWindow返回之前，会发送WM_CREATE消息
 33     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 300, NULL, NULL, hInst, NULL);
 34     if (hwnd == NULL)
 35     {
 36         MessageBox(NULL, TEXT("Create Window Fail!!"), TEXT("error"), MB_OK);
 37         return 0;
 38     }
 39     ShowWindow(hwnd, nShow);
 40     UpdateWindow(hwnd);
 41 
 42     while (GetMessage(&msg, NULL, 0, 0))
 43     {
 44         TranslateMessage(&msg);
 45         DispatchMessage(&msg);
 46     }
 47 
 48     return 0;
 49 }
 50 
 51 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 52 {
 53     PAINTSTRUCT pt;
 54     static int cx, cy;
 55     HDC hdc;
 56     HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 240));
 57     switch (message)
 58     {
 59     case WM_CREATE:
 60         SetWindowLong(hwnd, GWL_WNDPROC, (LONG)MyProc);
 61         return 0;
 62     case WM_SIZE:
 63         cx = LOWORD(lParam);
 64         cy = HIWORD(lParam);
 65         return 0;
 66     case WM_PAINT:
 67         InvalidateRect(hwnd, NULL, FALSE);
 68         hdc = BeginPaint(hwnd, &pt);
 69         HBRUSH hBrush = CreateSolidBrush(RGB(0, 255, 0));
 70         SelectObject(hdc, hBrush);
 71         Rectangle(hdc, 0, 0, cx / 2, cy / 2);
 72         DeleteObject(hBrush);
 73         EndPaint(hwnd, &pt);
 74         return 0;
 75     case WM_DESTROY:
 76         PostQuitMessage(0);
 77         return 0;
 78     default:
 79         break;
 80     }
 81 
 82     return DefWindowProc(hwnd, message, wParam, lParam);
 83 }
 84 
 85 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 86 {
 87     PAINTSTRUCT ps;
 88     HDC hdc;
 89     static int cx, cy;
 90 
 91     switch (message)
 92     {
 93     case WM_SIZE:
 94         cx = LOWORD(lParam);
 95         cy = HIWORD(lParam);
 96         break;
 97     case WM_PAINT:
 98         hdc = BeginPaint(hwnd, &ps);
 99         HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 0));
100         SelectObject(hdc, hBrush);
101         Rectangle(hdc, cx / 2, cy / 2, cx, cy);
102         DeleteObject(hBrush);
103         EndPaint(hwnd, &ps);
104         break;
105     default:
106         break;
107     }
108     return WindProc(hwnd, message, wParam, lParam);
109 }

View Code

方式② 源码

  1 #include<Windows.h>
  2 #include<Windowsx.h>
  3 
  4 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  5 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  6 
  7 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
  8 {
  9     WNDCLASS WndClass;
 10     TCHAR* ClassName = TEXT("MyClass");
 11     HWND hwnd;
 12     MSG msg;
 13     HBRUSH hBrush = CreateSolidBrush(RGB(200, 200, 200));
 14 
 15     WndClass.cbClsExtra = 0;
 16     WndClass.cbWndExtra = 0;
 17     WndClass.hbrBackground = hBrush;
 18     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
 19     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
 20     WndClass.hInstance = hInst;
 21     WndClass.lpfnWndProc = WindProc;
 22     WndClass.lpszClassName = ClassName;
 23     WndClass.lpszMenuName = NULL;
 24     WndClass.style = CS_VREDRAW | CS_HREDRAW;
 25 
 26     if (!RegisterClass(&WndClass))
 27     {
 28         MessageBox(NULL, TEXT("Gegister Class Fail!!"), TEXT("error"), MB_OK);
 29         return 0;
 30     }
 31 
 32     //CreateWindow返回之前，会发送WM_CREATE消息
 33     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 300, NULL, NULL, hInst, NULL);
 34     if (hwnd == NULL)
 35     {
 36         MessageBox(NULL, TEXT("Create Window Fail!!"), TEXT("error"), MB_OK);
 37         return 0;
 38     }
 39     ShowWindow(hwnd, nShow);
 40     UpdateWindow(hwnd);
 41 
 42     while (GetMessage(&msg, NULL, 0, 0))
 43     {
 44         TranslateMessage(&msg);
 45         DispatchMessage(&msg);
 46     }
 47 
 48     return 0;
 49 }
 50 
 51 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 52 {
 53     PAINTSTRUCT pt;
 54     static int cx, cy;
 55     HDC hdc;
 56     RECT rect;
 57     HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 240));
 58     switch (message)
 59     {
 60     case WM_CREATE:
 61         SetWindowLong(hwnd, GWL_WNDPROC, (LONG)MyProc);
 62         return 0;
 63     case WM_SIZE:
 64         cx = LOWORD(lParam);
 65         cy = HIWORD(lParam);
 66         return 0;
 67     case WM_PAINT:
 68         rect.left = 0;
 69         rect.bottom = cy / 2;
 70         rect.right = cx / 2;
 71         rect.top = 0;
 72         InvalidateRect(hwnd, &rect, TRUE);
 73         hdc = BeginPaint(hwnd, &pt);
 74         HBRUSH hBrush = CreateSolidBrush(RGB(0,255,0));
 75         SelectObject(hdc, hBrush);
 76         Rectangle(hdc, 0, 0, cx/2, cy/2);
 77         DeleteObject(hBrush);
 78         EndPaint(hwnd, &pt);
 79         return 0;
 80     case WM_DESTROY:
 81         PostQuitMessage(0);
 82         return 0;
 83     default:
 84         break;
 85     }
 86 
 87     return DefWindowProc(hwnd, message, wParam, lParam);
 88 }
 89 
 90 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 91 {
 92     PAINTSTRUCT ps;
 93     HDC hdc;
 94     static int cx, cy;
 95 
 96     switch (message)
 97     {
 98     case WM_SIZE:
 99         cx = LOWORD(lParam);
100         cy = HIWORD(lParam);
101         break;
102     case WM_PAINT:
103         hdc = BeginPaint(hwnd, &ps);
104         HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 0));
105         SelectObject(hdc, hBrush);
106         Rectangle(hdc, cx / 2, cy / 2, cx, cy);
107         DeleteObject(hBrush);
108         EndPaint(hwnd, &ps);
109         break;
110     default:
111         break;
112     }
113     return WindProc(hwnd, message, wParam, lParam);
114 }

View Code

运行结果：

借助SetWindowLong创建白板窗口

源码

  1 #include<Windows.h>
  2 #include<Windowsx.h>
  3 
  4 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  5 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam);
  6 
  7 int WinMain(HINSTANCE hInst, HINSTANCE tmp, LPSTR szCmd, int nShow)
  8 {
  9     WNDCLASS WndClass;
 10     TCHAR* ClassName = TEXT("MyClass");
 11     HWND hwnd;
 12     MSG msg;
 13     HBRUSH hBrush = CreateSolidBrush(RGB(200, 200, 200));
 14 
 15     WndClass.cbClsExtra = 0;
 16     WndClass.cbWndExtra = 0;
 17     WndClass.hbrBackground = hBrush;
 18     WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
 19     WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
 20     WndClass.hInstance = hInst;
 21     WndClass.lpfnWndProc = WindProc;
 22     WndClass.lpszClassName = ClassName;
 23     WndClass.lpszMenuName = NULL;
 24     WndClass.style = CS_VREDRAW | CS_HREDRAW;
 25 
 26     if (!RegisterClass(&WndClass))
 27     {
 28         MessageBox(NULL, TEXT("Gegister Class Fail!!"), TEXT("error"), MB_OK);
 29         return 0;
 30     }
 31 
 32     //CreateWindow返回之前，会发送WM_CREATE消息
 33     hwnd = CreateWindow(ClassName, TEXT("Hello"), WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 300, NULL, NULL, hInst, NULL);
 34     if (hwnd == NULL)
 35     {
 36         MessageBox(NULL, TEXT("Create Window Fail!!"), TEXT("error"), MB_OK);
 37         return 0;
 38     }
 39     ShowWindow(hwnd, nShow);
 40     UpdateWindow(hwnd);
 41 
 42     while (GetMessage(&msg, NULL, 0, 0))
 43     {
 44         TranslateMessage(&msg);
 45         DispatchMessage(&msg);
 46     }
 47 
 48     return 0;
 49 }
 50 
 51 LRESULT CALLBACK WindProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 52 {
 53     PAINTSTRUCT pt;
 54     static int cx, cy;
 55     HDC hdc;
 56     RECT rect;
 57     HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 240));
 58     switch (message)
 59     {
 60     case WM_CREATE:
 61         SetWindowLong(hwnd, GWL_STYLE, (LONG)WS_POPUP);
 62         return 0;
 63     case WM_SIZE:
 64         cx = LOWORD(lParam);
 65         cy = HIWORD(lParam);
 66         return 0;
 67     case WM_PAINT:
 68         rect.left = 0;
 69         rect.bottom = cy / 2;
 70         rect.right = cx / 2;
 71         rect.top = 0;
 72         InvalidateRect(hwnd, &rect, TRUE);
 73         hdc = BeginPaint(hwnd, &pt);
 74         HBRUSH hBrush = CreateSolidBrush(RGB(0,255,0));
 75         SelectObject(hdc, hBrush);
 76         Rectangle(hdc, 0, 0, cx/2, cy/2);
 77         DeleteObject(hBrush);
 78         EndPaint(hwnd, &pt);
 79         return 0;
 80     case WM_DESTROY:
 81         PostQuitMessage(0);
 82         return 0;
 83     default:
 84         break;
 85     }
 86 
 87     return DefWindowProc(hwnd, message, wParam, lParam);
 88 }
 89 
 90 LRESULT CALLBACK MyProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 91 {
 92     PAINTSTRUCT ps;
 93     HDC hdc;
 94     static int cx, cy;
 95 
 96     switch (message)
 97     {
 98     case WM_SIZE:
 99         cx = LOWORD(lParam);
100         cy = HIWORD(lParam);
101         break;
102     case WM_PAINT:
103         hdc = BeginPaint(hwnd, &ps);
104         HBRUSH hBrush = CreateSolidBrush(RGB(0, 0, 0));
105         SelectObject(hdc, hBrush);
106         Rectangle(hdc, cx / 2, cy / 2, cx, cy);
107         DeleteObject(hBrush);
108         EndPaint(hwnd, &ps);
109         break;
110     default:
111         break;
112     }
113     return WindProc(hwnd, message, wParam, lParam);
114 }

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原文地址：https://www.cnblogs.com/kelamoyujuzhen/p/9340539.html