WinAPI的mouse_event如何模拟鼠标点击？有问题源码 谢谢

        uint MOUSEEVENTF_MOVE = 0x0001;
        uint MOUSEEVENTF_LEFTDOWN = 0x0002;
        uint MOUSEEVENTF_LEFTUP = 0x0003;

        [DllImport("user32.dll")]
        private static extern void mouse_event(uint dwFlags, uint dx, uint dy, uint dwData, uint dwExtraInfo);
        private void button1_Click(object sender, EventArgs e)
        {
            mouse_event(MOUSEEVENTF_LEFTDOWN, 370, 400, 0, 0);
            mouse_event(MOUSEEVENTF_LEFTUP, 370, 400, 0, 0);
            //为什么我上面这样，实现不了鼠标的单击？反倒搞得我的鼠标不见了
        }

那正确的模拟鼠标单击是要怎么做？
谢谢

[解决办法]
用sendmessage win32 api

http://www.jb51.net/article/21991.htm
[解决办法]
mouse_event发送的坐标是针对屏幕的，不是自己程序的，要区分这个，另外就是点击目标要处于活动状态