[System.Runtime.InteropServices.DllImport("user32")]
private static extern int mouse_event(int dwFlags,int dx,int dy, int cButtons, int dwExtraInfo);
const int MOUSEEVENTF_MOVE = 0x0001;
const int MOUSEEVENTF_LEFTDOWN = 0x0002;
const int MOUSEEVENTF_LEFTUP = 0x0004;
const int MOUSEEVENTF_RIGHTDOWN = 0x0008;
const int MOUSEEVENTF_RIGHTUP = 0x0010;
const int MOUSEEVENTF_MIDDLEDOWN = 0x0020;
const int MOUSEEVENTF_MIDDLEUP = 0x0040;
const int MOUSEEVENTF_ABSOLUTE = 0x8000;