实现功能：在现有DLL程序中向特定的EXE窗口中发送模拟键盘的消息
　　　　  使用API根据窗口标题递归查找特定的窗口句柄，之后模拟调用。

注意：keybd_event函数不能在VS下使用，所以用SendInput代替使用：

 1 int SelfFindWindows(HWND hMainWnd, char* lpName, BYTE keyvalue)  2 {  3     HWND hChildWnd = GetWindow(hMainWnd, GW_CHILD);  4      5     while (hChildWnd != NULL)  6     {     7         char lpChildString[32] ={0};  8         GetWindowText(hChildWnd, lpChildString, sizeof(lpChildString));  9         10         if (strstr(lpChildString, lpName)) 11         { 12             SetForegroundWindow(hChildWnd); 13             SetFocus(hChildWnd); 14             15             /*16             keybd_event(keyvalue, 0, 0, 0); 17             keybd_event(keyvalue, 0, KEYEVENTF_KEYUP, 0); 18             */19             INPUT input[2];20             memset(input, 0, sizeof(input));21             //按下 向下方向键22             input[0].ki.wVk = keyvalue;23             input[0].type = INPUT_KEYBOARD;    24             //松开 向下方向键25             input[1].ki.wVk = keyvalue;26             input[1].type = INPUT_KEYBOARD;27             input[1].ki.dwFlags = KEYEVENTF_KEYUP;28             //该函数合成键盘事件和鼠标事件，用来模拟鼠标或者键盘操作。事件将被插入在鼠标或者键盘处理队列里面29             SendInput(2, input, sizeof(INPUT));        30             return 1; 31         } 32         33         if (GetWindow(hChildWnd, GW_CHILD)) 34         { 35             if (SelfFindWindows(hChildWnd, lpName, keyvalue)) 36             { 37                 return 1; 38             } 39         } 40     else 41         hChildWnd = GetWindow(hChildWnd, GW_HWNDNEXT); 42     } 43 44     return 0; 45 } 46 47 int SendKeyEventToEXE() 48 { 49     HWND hDesk = GetDesktopWindow(); 50     HWND hWnd = GetWindow(hDesk, GW_CHILD); 51     52     while (hWnd != NULL) 53     {    54         char lpString[32] ={0}; 55         GetWindowText(hWnd, lpString, sizeof(lpString)); 56         57         if (strstr(lpString, "Foxit Reader")) 58         { 59             SelfFindWindows(hWnd, "Reader", VK_NEXT);    60         61             return 1; 62         } 63         64         hWnd = GetWindow(hWnd, GW_HWNDNEXT); 65     } 66     return 0; 67 }