Windows应用程序对键盘与鼠标的响应

 

编写程序: 设计一个窗口, 当单击鼠标左键时, 窗口中显示"LEFT BUTTON"; 当单击鼠标右键时, 窗口中显示"RIGHT BUTTON"; 当单击向上箭头键时, 窗口中显示"UP Key"; 当单击Ctrl键时, 窗口中显示"CTRL Key"; 当单击 Ctrl+A 键时, 窗口中显示"CTRL+A Key":

程序主要代码如下:

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)

{

    int wmId, wmEvent;

    PAINTSTRUCT ps;

    HDC hDC;

    //TCHAR szHello[MAX_LOADSTRING];

    //LoadString(hInst, IDS_HELLO, szHello, MAX_LOADSTRING);

    static char cLEFT[]="LEFT BUTTON";

    static char cRIGHT[]="RIGHT BUTTON";

    static char cUp[]="UP key";

    static char cCTRL[]="CTRL key";

    static char cCTRLA[]="CTRL+A key";

    static BOOL nUpKeyDown=FALSE, nCtrlKeyDown=FALSE, nCtrlAKeyDown=FALSE,nLeftDown=FALSE,nRightDown=FALSE;

    int xOrg,yOrg;

    switch (message)

    {

        case WM_KEYDOWN:

        {

            switch(wParam)

            {

            case VK_UP:

                nUpKeyDown=TRUE;

                break;

            case VK_CONTROL:

                nCtrlKeyDown=TRUE;

                break;

            

            default:

                break;

            }

        }

            break;

 

        case WM_KEYUP:

            InvalidateRect(hWnd,NULL,TRUE);    //刷新用户区。

            break;

        case WM_CHAR:

            {

                    if(wParam==(65&VK_CONTROL))    

                    {

                        if(nCtrlKeyDown == TRUE)

                        {

                            nCtrlAKeyDown = TRUE;

                            nCtrlKeyDown = FALSE;

                        }

                    }

                    

                }

                break;

        case WM_LBUTTONDOWN:

            nLeftDown=TRUE;

            InvalidateRect(hWnd,NULL,TRUE);    //刷新用户区。

            break;

        case WM_RBUTTONDOWN:

            nRightDown=TRUE;

            InvalidateRect(hWnd,NULL,TRUE);    //刷新用户区。

            break;

 

        case WM_COMMAND:

            wmId = LOWORD(wParam);

            wmEvent = HIWORD(wParam);

            // Parse the menu selections:

            switch (wmId)

            {

                case IDM_ABOUT:

                 DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);

                 break;

                case IDM_EXIT:

                 DestroyWindow(hWnd);

                 break;

                default:

                 return DefWindowProc(hWnd, message, wParam, lParam);

            }

            break;

        case WM_PAINT:

            hDC = BeginPaint(hWnd, &ps);

            // TODO: Add any drawing code here...

            RECT rt;

            GetClientRect(hWnd, &rt);

            xOrg=(rt.left+rt.right)/2;

            yOrg=(rt.top +rt.bottom)/2;

            if(nUpKeyDown == TRUE)

            {

                TextOut(hDC,xOrg,yOrg,cUp,strlen(cUp));

                nUpKeyDown = FALSE;

（续前表）

}

            else if(nCtrlAKeyDown == TRUE)

            {

                TextOut(hDC,xOrg,yOrg,cCTRLA,strlen(cCTRLA));

                nCtrlAKeyDown = FALSE;

                nCtrlKeyDown = FALSE;

            }

            else if(nCtrlKeyDown == TRUE&&nCtrlAKeyDown == FALSE)

            {

                TextOut(hDC,xOrg,yOrg,cCTRL,strlen(cCTRL));

                nCtrlKeyDown = FALSE;

            }

            else if(nLeftDown == TRUE)

            {

                TextOut(hDC,xOrg,yOrg,cLEFT,strlen(cLEFT));

                nLeftDown = FALSE;

            }

            else if(nRightDown == TRUE)

            {

                TextOut(hDC,xOrg,yOrg,cRIGHT,strlen(cRIGHT));

                nRightDown = FALSE;

            }

    
 

            //DrawText(hdc, lpString, _tcsclen(lpString), &rt, DT_CENTER);

            EndPaint(hWnd, &ps);

            break;

        case WM_DESTROY:

            PostQuitMessage(0);

            break;

        default:

            return DefWindowProc(hWnd, message, wParam, lParam);

}

return 0;

}

 

编译并调试程序

程序运行结果运行结果如下图：

单击鼠标左键

单击鼠标右键

单击向上箭头

单击Ctrl键

单击Ctrl+A

刚开始刷新客户区时使用

InvalidateRect(hWnd,NULL,FALSE);

结果导致背景客户区背景不更新，输出的文本重叠，了解了InvalidateRect()的使用方式后，将语句改为

InvalidateRect(hWnd,NULL,TRUE);

即成功解决了问题；