模拟键盘'a'输入
keybd_event(65,0,KEYEVENTF_EXTENDEDKEY,0); //KEYDOWN，
keybd_event(65,0,KEYEVENTF_EXTENDEDKEY or KEYEVENTF_KEYUP,0); //KEYUP
以上可成功实现，但我想按模拟Ctrl+Shift切换输入法
keybd_event(VK_MODECHANGE,0,KEYEVENTF_EXTENDEDKEY,0); //KEYDOWN，
keybd_event(VK_MODECHANGE,0,KEYEVENTF_EXTENDEDKEY or KEYEVENTF_KEYUP,0); //KEYUP
却不能实现，谁能帮忙。为什么？？？？