第7章 鼠标_7.1-7.4 鼠标基础知识和鼠标消息

7.1 鼠标的基础知识

功能	GetSysMetrics的 参数	返回值
判断是否安装鼠标	SM_MOUSEPRESENT	WINNT以上：TRUE己安装。0未安装 Windows98：总是TRUE。
鼠标按钮个数	SM_CMOUSEBUTTONS	WINNT以上：0为未安装鼠标 Windows98：有安装鼠标返回按钮个数，没安装鼠标返回2。
鼠标按钮是否被切换	SM_SWAPBUTTON

设定鼠标其他参数（如双击）：用SystemParametrsInfo函数获取或设定

（2）鼠标指针：wndClass.hCursor = LoadCursor(NULL,IDC_ARROW)。

7.2 客户区的鼠标消息

（1）客户区鼠标消息（10个）

事件	消息
鼠标经过	WM_MOUSEMOVE
左键	WM_LBUTTONDOWN、WM_LBUTTONUP、WM_LBUTTONDBLCLK(双击)
中键	WM_MBUTTONDOWN、WM_MBUTTONUP、WM_MBUTTONDBLCLK（第二次按下）
右键	WM_RBUTTONDOWN、WM_RBUTTONUP、WM_RBUTTONDBLCLK

  说明：①双击事件的处理只有窗口类定义接收时，才起作用：即

差异	没包含双击事件	包含双击事件
wndClass.style	CS_HREDRAW| CS_VREDRAW	CS_HREDRAW | CS_VREDRAW|CS_DBLCLKS
消息顺序	WM_LBUTTONDOWN WM_LBUTTONUP WM_LBUTTONDOWN WM_LBUTTONUP	WM_LBUTTONDOWN WM_LBUTTONUP WM_LBUTTONDBLCLK WM_LBUTTONUP

        ②MBUTTON只对三键鼠标起作用。单键鼠标只处理LBUTTON消息。

③WM_MOUSEMOVE：消息的个数取决于鼠标硬件和窗口处理的速度。Windows不会为

经过的每个像素位置都产生一个WM_MOUSEMOVE消息。

        ④WM_LBUTTONDOWN和WM_LBUTTONUP并不一定会成对出现。可能只收到其中的一种

消息。

⑤键盘消息发送到当前具有输入焦点的窗口。鼠标消息发送给被单击的窗或鼠标经

过的窗口，即使该窗口处于非活动或不带输入焦点。两种例外：A、“捕获鼠标”

时，鼠标离开窗口仍继续接收鼠标消息;B、模式对话框处于活动状态时，其他

程序不能接收鼠标消息。

 （2）鼠标消息的参数

wParam(按钮、Shift、Ctrl键状态)	lParam（鼠标位置）
MK_LBUTTON（0x0001）：按下左键 MK_RBUTTON（0x0002）：按下右键 MK_SHIFT  （0x0004）：按下Shift MK_CONTROL（0x0008）：按下Ctrl MK_MBUTTON（0x0010）：按下中键 ★或运算结果	x = LOWORD(lParam); y = HIWORD(lParam);

       eg.当WM_LBUTTONDOWN时，是否同时按下Shift键：wParam & MK_SHIFT。

7.2.1 简单的鼠标处理示例

【Connect程序】

（1）操作方法：

①第一种——在客户区按下左键，略微移动，再松开左键

②第二种——在客户区按下左键，快速移动鼠标。

（2）己知的问题：在客户区外释放左键，Connnect不会连接这些点，因为没收到WM_LBUTTONUP消息。

（3）该程序较耗时，绘制时，鼠标变沙漏形，处理WM_PAINT完后回原来的状态。用SetCursor来切换鼠标。ShowCursor隐藏或显示鼠标指针。

 【效果图】

 

 

/*------------------------------------------------------------
CONNECT.C -- Connect-the-Dots Mouse Demo program
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#define MAXPOINTS 1000
#include <windows.h>
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Connect");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Connect-the-Points Mouse Demo"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC         hdc;
    PAINTSTRUCT ps;
    static POINT pt[MAXPOINTS];
    static int iCount = 0;
    switch (message)
    {
    case WM_LBUTTONDOWN:
        iCount = 0;
        InvalidateRect(hwnd, NULL, TRUE); //每次按下左键时，先消屏
        return 0;
    case WM_MOUSEMOVE:  //验证移动时，并不是每个像素都产生WM_MOUSEMOVE消息。
        if (wParam & MK_LBUTTON && iCount<MAXPOINTS) //只有按下左键+鼠标移动时，才画点
        {
            pt[iCount].x = LOWORD(lParam);
            pt[iCount++].y = HIWORD(lParam);

            //画点
            hdc = GetDC(hwnd);
            SetPixel(hdc, LOWORD(lParam), HIWORD(lParam), 0);
            ReleaseDC(hwnd, hdc);
        }
        return 0;
    case WM_LBUTTONUP:  //鼠标放开时，开始连线
        InvalidateRect(hwnd, NULL, FALSE); //FALSE，不擦除背景，可以保留WM_MOUSEMOVE里画下的点。
        return 0;

    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        SetCursor(LoadCursor(NULL, IDC_WAIT));
        ShowCursor(TRUE); //鼠标指针显示为等待状态
        for (int i = 0; i < iCount; i++)   //每一点而其他各点的连线
        for (int j = i + 1; j < iCount; j++)
        {
            MoveToEx(hdc, pt[i].x, pt[i].y, NULL);
            LineTo(hdc, pt[j].x, pt[j].y);
        }
        ShowCursor(FALSE);
        SetCursor(LoadCursor(NULL, IDC_ARROW));
        EndPaint(hwnd, &ps);
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

7.2.2 处理Shift键

处理过程依赖Shift和Ctrl键的逻辑处理	单键鼠标模拟双键鼠标
if (wParam & MK_SHIFT)  //按下Shift {     if (wParam & MK_CONTROL)     {         [按下Shift + Ctrl键];      }     else{         [只按下Shift键];     } }else{                  //未按Shift     if (wParam & MK_CONTROL)     {         [只按下Ctrl键];     }else{         [Shift和Ctrl都没被按下];     } }	case WM_LBUTTONDOWN: //未按Shift时，直接处理左键     if (!(wParam & MK_SHIFT))     {         [这里处理左键];         return 0;      }   //注意，这里没有return。     //用户按下了鼠标左键+Shift，执行以下代码，模拟右键。 case WM_RBUTTONDOWN:      [这里处理右键];     return 0; ★注意：双键鼠标也是可以正常处理的。单键鼠标可以通过按住鼠标左键+Shift，来模拟鼠标右键的功能。

注意：GetKeyState可以通过VK_LBUTTON、VK_RBUTTON、VK_SHIFT、VK_CONTROL等获取鼠标当前状态。但鼠标或键盘未被按下的键不能使用GetKeyState。只有被按下时才会报告其按下状态。（while(GetKeyState(VK_LBUTTON)>=0)）是错误的代码。

7.3 非客户区的鼠标消息

（1）非客户区鼠标消息（11个）

事件	消息
鼠标经过	WM_NCMOUSEMOVE
击中测试	WM_NCHITTEST
左键	WM_NCLBUTTONDOWN、WM_NCLBUTTONUP、WM_NCLBUTTONDBLCLK(双击)
中键	WM_NCMBUTTONDOWN、WM_NCMBUTTONUP、WM_NCMBUTTONDBLCLK（第二次按下）
右键	WM_NCRBUTTONDOWN、WM_NCRBUTTONUP、WM_NCRBUTTONDBLCLK

 （2）非客户区鼠标消息的参数

wParam（窗口的哪个部位） （20多个位置，见MSDN）	lParam（鼠标屏幕坐标）
HTCLINET  客户区 HTNOWHERE 不在任何窗口 HTRANSPARENT 被另一个窗口覆盖 HTERROR  使函数DefWindowProc产生警示声 ……	Pt.x =LOWORD(lParam); Pt.y =HIWORD(lParam); //屏幕坐标与客户区坐标转换 ScreenToClient(hwnd,&pt); ClientToScreen(hwnd,&pt);

7.3.1 击中测试消息：WM_NCHITTEST

（1）消息优先级高于其他鼠标消息

（2）wParam参数如上表所示。

（3）DefWindowProc在处理WM_NCHITTEST后，如果返回HTCLIENT，则会把屏幕坐标转成客户区坐标，并产生一个客户区鼠标消息。

（4）使鼠标按钮操作失效——阻止系统向窗口发送所有客户区和非客户区鼠标消息：

       case WM_NCHITTEST:return (LRESULT)HTNOWHERE;

7.3.2 消息引发的消息

（1）Windows利用WM_NCHITTEST来产生其他所有的鼠标消息。

（2）举例：双击系统图标来关闭窗口，由WM_NCHITTEST引发的消息

顺序	当前消息	wParam	返回
1、双击系统图标，产生WM_NCHITTEST，由DefWindowProc处理后，产生下一条消息。	WM_NCHITTEST	Not used	HTSYSMENU
2、默认处理后，再产生下条消息	WM_NCLBUTTONDBLCLK	HTSYSMENU
3、默认处理后，产生下条消息	WM_SYSCOMMAND	SC_CLOSE
4、DefWindowProc调用DestroyWindow处理这条消息，并产生下条消息	WM_CLOSE
5、默认处理或用户处理，并销毁。	WM_DESTROY

7.4 程序中的击中测试

7.4.1 一个简单的程序

（1）矩形宽度为cxBlock，高度为cyBlock

（2）WM_LBUTTONDOWN判断鼠标落在哪个矩形内

（3）如果客户区宽度和长度不能被5整除，会在左边和底部出现一个空白区。

（4）点击鼠标时产生一个无效区（矩形），并发送WM_PAINT重新绘制该无效区。
【效果图】

 

/*------------------------------------------------------------
CHECKER1.C -- Mouse Hit-Test demo Program No.2
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define  DIVISIONS 5
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Checker1");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Checker1 Mouse Hit-Test Demo"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC         hdc;
    PAINTSTRUCT ps;
    RECT        rect;
    static cxBlock, cyBlock;
    static BOOL fState[DIVISIONS][DIVISIONS];
    int x, y;
    switch (message)
    {
    case WM_CREATE:

        return 0;
    case WM_SIZE:
        cxBlock = LOWORD(lParam) / DIVISIONS;
        cyBlock = HIWORD(lParam) / DIVISIONS;
        return 0;
    case WM_LBUTTONDOWN:
        //单击的矩形索引
        x = LOWORD(lParam) / cxBlock;
        y = HIWORD(lParam) / cyBlock;
        if (x < DIVISIONS && y < DIVISIONS)
        {
            fState[x][y] ^= 1; //即fState[x][y] =!fState[x][y];
            rect.top = y*cyBlock;
            rect.bottom = (y + 1)*cyBlock;
            rect.left = x*cxBlock;
            rect.right = (x + 1)*cxBlock;
            InvalidateRect(hwnd, &rect, TRUE); //因用透明绘制，所以要清除背景
        }
        else{
            //当宽度和长度不是5个倍数时，会在左或底侧出现个空白区，让其发出错误的声音。
            MessageBeep(0);
        }
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        RECT tmpRect;
        SelectObject(hdc, GetStockObject(NULL_BRUSH));//透明绘制
        for (int x = 0; x < DIVISIONS; x++)
        for (int y = 0; y < DIVISIONS; y++)
        {
            rect.top = y*cyBlock;
            rect.bottom = (y + 1)*cyBlock;
            rect.left = x*cxBlock;
            rect.right = (x + 1)*cxBlock;
            IntersectRect(&tmpRect, &rect, &ps.rcPaint);
            if (IsRectEmpty(&tmpRect)) continue;//判断当前矩形区是否在无效区内

            Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);

            if (fState[x][y])
            {
                MoveToEx(hdc, x*cxBlock, y*cyBlock, NULL);
                LineTo(hdc, (x + 1)*cxBlock, (y + 1)*cyBlock);
                MoveToEx(hdc, x*cxBlock, (y + 1)*cyBlock, NULL);
                LineTo(hdc, (x + 1)*cxBlock, y*cyBlock);
            }
        }

        EndPaint(hwnd, &ps);
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

7.4.2 使用键盘模仿鼠标操作

（1）显示或隐藏鼠标

   ShowCursor（TRUE）；//增加鼠标显示计数，默认0，只有在>=0时，才显示。

   ShowCursor(FALSE)；//减少鼠标计数，只有在<0时才隐藏。

（2）获取和设置鼠标位置

   ①Get、Set鼠标位置

      GetCursorPos(&pt);//屏幕坐标（因为没有hwnd参数），可与客户区坐标转换

      SetCursorPos(&pt);

   ②GetCursorPos与鼠标消息的参数lParam的差别。

      A、GetCursorPos坐标并转成客户区坐标，返回的鼠标当前位置

      B、lParam包含的坐标是指产生消息的那一刻的鼠标位置。

 （3）在CHECKER中增加键盘接口

    ①用空格与Enter键模拟鼠标按钮；方向键每按一次切换到另一个矩形。

    ②Home键回到左上角的矩形，End键鼠标落到右下角矩形。

 【Checker2程序】

/*------------------------------------------------------------
CHECKER2.C -- Mouse Hit-Test demo Program No.2
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define  DIVISIONS 5
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Checker2");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Checker2 Mouse Hit-Test Demo"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC         hdc;
    PAINTSTRUCT ps;
    RECT        rect;
    static cxBlock, cyBlock;
    static BOOL fState[DIVISIONS][DIVISIONS];
    int x, y;
    POINT pt;
    switch (message)
    {
    case WM_CREATE:

        return 0;
    case WM_SIZE:
        cxBlock = LOWORD(lParam) / DIVISIONS;
        cyBlock = HIWORD(lParam) / DIVISIONS;
        return 0;
    case WM_SETFOCUS:
        ShowCursor(TRUE); //显示鼠标，现在都安装了鼠标，可以省略
        return 0;
    case WM_KILLFOCUS:
        ShowCursor(FALSE);
        return 0;
    case WM_KEYDOWN:

        GetCursorPos(&pt); //因wParam为虚拟键，lParam为击键的6个字段，没鼠标坐标。
        ScreenToClient(hwnd, &pt);

        //当前选中的矩形
        x = max(0, min(DIVISIONS - 1, pt.x / cxBlock));    //限定在[0-4]之间
        y = max(0, min(DIVISIONS - 1, pt.y / cyBlock));
        switch (wParam)
        {
        case VK_UP:
            y--;
            break;
        case VK_DOWN:
            y++;
            break;
        case VK_LEFT:
            x--;
            break;
        case VK_RIGHT:
            x++;
            break;
        case VK_HOME:
            x = y = 0;
            break;
        case VK_END:
            x = y = DIVISIONS - 1;
        case VK_SPACE:
        case VK_RETURN:
            SendMessage(hwnd, WM_LBUTTONDOWN, MK_LBUTTON, MAKELONG(x*cxBlock, y*cyBlock));
            return 0;//也可以break，执行下面代码，将鼠标设置到当前矩形中央位置。
        }
        x = (x + DIVISIONS) % DIVISIONS; //x原区间为[0，4]，移到[5,9]区间，防止x--后出现负数区间。
        y = (y + DIVISIONS) % DIVISIONS;

        //设置鼠标位置到矩形中央位置
        pt.x = x*cxBlock + cxBlock / 2;
        pt.y = y*cyBlock + cyBlock / 2;
        ClientToScreen(hwnd, &pt); //客户区坐标转成屏幕坐标
        SetCursorPos(pt.x, pt.y);
        return 0;
    case WM_LBUTTONDOWN:
        //单击的矩形索引
        x = LOWORD(lParam) / cxBlock;
        y = HIWORD(lParam) / cyBlock;
        if (x < DIVISIONS && y < DIVISIONS)
        {
            fState[x][y] ^= 1; //即fState[x][y] =!fState[x][y];
            rect.top = y*cyBlock;
            rect.bottom = (y + 1)*cyBlock;
            rect.left = x*cxBlock;
            rect.right = (x + 1)*cxBlock;
            InvalidateRect(hwnd, &rect, TRUE); //因用透明绘制，所以要清除背景
        }
        else{
            //当宽度和长度不是5个倍数时，会在左或底侧出现个空白区，让其发出错误的声音。
            MessageBeep(0);
        }
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        RECT tmpRect;
        SelectObject(hdc, GetStockObject(NULL_BRUSH));//透明绘制
        for (int x = 0; x < DIVISIONS; x++)
        for (int y = 0; y < DIVISIONS; y++)
        {
            rect.top = y*cyBlock;
            rect.bottom = (y + 1)*cyBlock;
            rect.left = x*cxBlock;
            rect.right = (x + 1)*cxBlock;
            IntersectRect(&tmpRect, &rect, &ps.rcPaint);
            if (IsRectEmpty(&tmpRect)) continue;//判断当前矩形区是否在无效区内

            Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);

            if (fState[x][y])
            {
                MoveToEx(hdc, x*cxBlock, y*cyBlock, NULL);
                LineTo(hdc, (x + 1)*cxBlock, (y + 1)*cyBlock);
                MoveToEx(hdc, x*cxBlock, (y + 1)*cyBlock, NULL);
                LineTo(hdc, (x + 1)*cxBlock, y*cyBlock);
            }
        }

        EndPaint(hwnd, &ps);
        return 0;

    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

7.4.3 在击中测试中使用子窗口

（1）包含25个子窗口，两个窗口过程：WndProc和ChildWndProc

（2）子窗口类的cbWndExtra设置4个字节，用来保存该窗口绘画状态，打“X”用1表示。

（3）WndProc中创建子窗口时须调用GetWindowsLong,从注册的窗口结构中提取hInstance.

（4）hwndChild数组为每个子窗口保存了窗口句柄，MoveWindows函数中要用到。

（5）CreateWindows主窗口与子窗口参数的比较

参数	主窗口	子窗口
窗口类	“Checker3”	“Checker3_Child”
窗口标题	“Checker3…”	NULL
窗口风格	WS_OVERLAPPEDWINDOW	WS_CHILDWINDOW|WS_VISIBLE
水平位置	CW_USEDEFAULT	0
垂直位置	CW_USEDEFAULT	0
宽度	CW_USEDEFAULT	0
高度	CW_USEDEFAULT	0
父窗口句柄	NULL	hwnd
菜单句柄/子ID	NULL	（HMENU）（y<<8 | x）（唯一标识子窗口的数值）
实例句柄	hInstance	(HINSTANCE)GetWindowLong(hwnd,GWL_INSTANCE)
额外参数	NULL	NULL

【Checker3程序】

/*------------------------------------------------------------
CHECKER3.C -- Mouse Hit-Test demo Program No.3
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define  DIVISIONS 5
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); //主窗口过程
LRESULT CALLBACK ChildWndProc(HWND, UINT, WPARAM, LPARAM);  //子窗口的窗口过程
TCHAR szChildClass[] = TEXT("Checker_Child"); //须定义为全局变量，因为WinMain和WndProc中都要用到。
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Checker3");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    //主窗体
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    //子窗口类
    wndclass.lpfnWndProc = ChildWndProc;
    wndclass.cbWndExtra = sizeof(long); //也可以为设置，直接保存在窗体的GWL_USERDATA中
    wndclass.hIcon = NULL;
    wndclass.lpszClassName = szChildClass;
    RegisterClass(&wndclass); //己经是NT了，不需要再检查了。
    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Checker3 Mouse Hit-Test demo"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndChild[DIVISIONS][DIVISIONS];
    static int cxBlock, cyBlock;
    switch (message)
    {
    case WM_CREATE:
        for (int x = 0; x < DIVISIONS; x++)
        for (int y = 0; y < DIVISIONS; y++)
        {
            hwndChild[x][y] = CreateWindow(szChildClass, NULL,
                WS_CHILD | WS_VISIBLE, //没WS_VISIBLE时，创建好窗口，要自己ShowWindow
                0, 0, 10, 10,
                hwnd,
                (HMENU)(y << 8 | x),
                (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), //从主窗体获得hInstance 
                NULL);
        }
        return 0;
    case WM_SIZE:
        cxBlock = LOWORD(lParam) / DIVISIONS;
        cyBlock = HIWORD(lParam) / DIVISIONS;
        for (int x = 0; x < DIVISIONS; x++)
        for (int y = 0; y < DIVISIONS; y++)
        {
            MoveWindow(hwndChild[x][y], x*cxBlock, y*cyBlock, cxBlock, cyBlock, TRUE);
        }
        return 0;
    case WM_LBUTTONDOWN:
        MessageBeep(0);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}
LRESULT CALLBACK ChildWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC         hdc;
    PAINTSTRUCT ps;
    RECT        rect;
    switch (message)
    {
    case WM_CREATE:
        SetWindowLong(hwnd, 0, 0);//开/关标记，保存cbWndExtra空间
        //SetWindowLong(hwnd, GWL_USERDATA, 0);//保存在USERDATA中
        return 0;
    case WM_LBUTTONDOWN:
        SetWindowLong(hwnd, 0, 1 ^ GetWindowLong(hwnd, 0));
        //SetWindowLong(hwnd, GWL_USERDATA, 1 ^ GetWindowLong(hwnd, GWL_USERDATA));
        InvalidateRect(hwnd, NULL, FALSE); //因为矩形默认是填充白色的，会覆盖之前绘画，所以用False
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        GetClientRect(hwnd, &rect);
        Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
        if (GetWindowLong(hwnd, 0)) //if (GetWindowLong(hwnd, GWL_USERDATA))
        {
            MoveToEx(hdc, rect.left, rect.top, NULL);
            LineTo(hdc, rect.right, rect.bottom);
            MoveToEx(hdc, rect.left, rect.bottom, NULL);
            LineTo(hdc, rect.right, rect.top);
        }
        EndPaint(hwnd, &ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}

7.4.4 子窗口和键盘

（1）单击子窗口时，得到输入焦点的是父窗口，而不是子窗口。（记这点很重要）。鼠标但键盘消息只给被具有焦点的窗口接收。（父子窗口如何共享键盘消息呢？如，当按空格或回车键时，接收消息的是子窗口，要反转选中状态。按方向键时，接收消息的是父窗口，要将焦点移到另一个子窗口上？方法：父窗口直接将焦点转移给子窗口，让子窗口接管键盘消息，子窗体先处理回车键和空格键等键盘消息。但遇到方向键时，将消息通过SendMessage返给父窗口，注意这个过程不必将焦点还给父窗口。整个过程，即父窗口将键盘消息让给子窗口去接管，子窗口处理自己兴趣的消息，把不处理的消息重新分发给父窗口）

（2）父窗口中操作子窗口

操作	函数
获取子窗口ID的方法	idChild = GetWindowLong(hwndChild，GWL_ID); idChild = GetDlgCtrlID(hwndChild)
获取子窗口的句柄	hwndChild = GetDlgItem(hwndParent,idChild)
设置子窗口为焦点窗口	SetFocus(GetDlgItem(hwnd,idFocus))

（3）子窗口得到焦点时：WM_SETFOCUS中画虚线框表示
【Checker4】 

/*------------------------------------------------------------
CHECKER4.C -- Mouse Hit-Test demo Program No.3
(c) Charles Petzold, 1998
------------------------------------------------------------*/
#include <windows.h>
#define  DIVISIONS 5
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); //主窗口过程
LRESULT CALLBACK ChildWndProc(HWND, UINT, WPARAM, LPARAM);  //子窗口的窗口过程
TCHAR szChildClass[] = TEXT("Checker_Child"); //须定义为全局变量，因为WinMain和WndProc中都要用到。
int idFocus; //当前选中的矩形（用子窗口ID来标识）
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    PSTR szCmdLine, int iCmdShow)
{
    static TCHAR szAppName[] = TEXT("Checker4");
    HWND         hwnd;
    MSG          msg;
    WNDCLASS     wndclass;
    //主窗体
    wndclass.style = CS_HREDRAW | CS_VREDRAW;
    wndclass.lpfnWndProc = WndProc;
    wndclass.cbClsExtra = 0;
    wndclass.cbWndExtra = 0;
    wndclass.hInstance = hInstance;
    wndclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
    wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wndclass.lpszMenuName = NULL;
    wndclass.lpszClassName = szAppName;
    if (!RegisterClass(&wndclass))
    {
        MessageBox(NULL, TEXT("This program requires Windows NT!"),
            szAppName, MB_ICONERROR);
        return 0;
    }

    //子窗口类
    wndclass.lpfnWndProc = ChildWndProc;
    wndclass.cbWndExtra = sizeof(long);
    wndclass.hIcon = NULL;
    wndclass.lpszClassName = szChildClass;
    RegisterClass(&wndclass); //己经是NT了，不需要再检查了。
    hwnd = CreateWindow(szAppName,                  // window class name
        TEXT("Checker4 Mouse Hit-Test demo"), // window caption
        WS_OVERLAPPEDWINDOW,        // window style
        CW_USEDEFAULT,              // initial x position
        CW_USEDEFAULT,              // initial y position
        CW_USEDEFAULT,              // initial x size
        CW_USEDEFAULT,              // initial y size
        NULL,                       // parent window handle
        NULL,                       // window menu handle
        hInstance,                  // program instance handle
        NULL);                     // creation parameters

    ShowWindow(hwnd, iCmdShow);
    UpdateWindow(hwnd);

    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static HWND hwndChild[DIVISIONS][DIVISIONS];
    static int cxBlock, cyBlock;
    int x, y;
    switch (message)
    {
    case WM_CREATE:
        for (int x = 0; x < DIVISIONS; x++)
        for (int y = 0; y < DIVISIONS; y++)
        {
            hwndChild[x][y] = CreateWindow(szChildClass, NULL,
                WS_CHILD | WS_VISIBLE, //没WS_VISIBLE时，创建好窗口，要自己ShowWindow
                0, 0, 10, 10,
                hwnd,
                (HMENU)(y << 8 | x),
                (HINSTANCE)GetWindowLong(hwnd, GWL_HINSTANCE), //从主窗体获得hInstance 
                NULL);
        }
        return 0;
    case WM_SIZE:
        cxBlock = LOWORD(lParam) / DIVISIONS;
        cyBlock = HIWORD(lParam) / DIVISIONS;
        for (int x = 0; x < DIVISIONS; x++)
        for (int y = 0; y < DIVISIONS; y++)
        {
            MoveWindow(hwndChild[x][y], x*cxBlock, y*cyBlock, cxBlock, cyBlock, TRUE);
        }
        return 0;
    case WM_SETFOCUS:
        SetFocus(GetDlgItem(hwnd, idFocus)); //将子窗体设置为窗口窗体，以便接管键盘消息。
        return 0;
    case WM_KEYDOWN:
        x = idFocus & 0xFF;
        y = idFocus >> 8;
        switch (wParam)
        {
        case VK_UP:      y--; break;
        case VK_DOWN:    y++; break;
        case VK_LEFT:    x--; break;
        case VK_RIGHT:   x++; break;
        case VK_HOME:    x = y = 0; break;
        case VK_END:     x = y = DIVISIONS - 1; break;
        default: return 0; //其它按键不处理，直接返回
        }

        x = (x + DIVISIONS) % DIVISIONS;
        y = (y + DIVISIONS) % DIVISIONS;
        idFocus = y << 8 | x;
        SetFocus(GetDlgItem(hwnd, idFocus));
        return 0;
    case WM_LBUTTONDOWN:
        MessageBeep(0);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}
LRESULT CALLBACK ChildWndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    HDC         hdc;
    PAINTSTRUCT ps;
    RECT        rect;
    switch (message)
    {
    case WM_CREATE:
        SetWindowLong(hwnd, 0, 0);//开/关标记，保存cbWndExtra空间
        return 0;
    case WM_KEYDOWN:
        //将绝大部分的键盘消息还给父窗口处理
        if (wParam != VK_RETURN && wParam != VK_SPACE)
        {
            SendMessage(GetParent(hwnd), message, wParam, lParam);
            return 0;
        }
        //继续执行下去，处理回车和空格键
    case WM_LBUTTONDOWN:
        SetWindowLong(hwnd, 0, 1 ^ GetWindowLong(hwnd, 0));
        SetFocus(hwnd);
        InvalidateRect(hwnd, NULL, FALSE); //因为矩形默认是填充白色的，会覆盖之前绘画，所以用False
        return 0;
    case WM_SETFOCUS:
        idFocus = GetWindowLong(hwnd, GWL_ID);
        //继续执行下去，用虚线框表示焦点窗口

    case WM_KILLFOCUS:
        InvalidateRect(hwnd, NULL, TRUE);
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        GetClientRect(hwnd, &rect);
        Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
        if (GetWindowLong(hwnd, 0))
        {
            MoveToEx(hdc, rect.left, rect.top, NULL);
            LineTo(hdc, rect.right, rect.bottom);
            MoveToEx(hdc, rect.left, rect.bottom, NULL);
            LineTo(hdc, rect.right, rect.top);
        }

        if (hwnd == GetFocus())
        {
            rect.left += rect.right / 20;
            rect.right -= rect.left;
            rect.top += rect.bottom / 20;
            rect.bottom -= rect.top;
            SelectObject(hdc, GetStockObject(NULL_BRUSH));
            SelectObject(hdc, CreatePen(PS_DOT, 0, 0));
            Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
            DeleteObject(SelectObject(hdc, GetStockObject(BLACK_PEN)));
        }
        EndPaint(hwnd, &ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return DefWindowProc(hwnd, message, wParam, lParam);
}