private static extern UInt32 SendInput(UInt32 nInputs, ref INPUT pInputs, int cbSize);
public static void KeybdEvent(byte key, byte bScan, KeybdEventFlag flags, uint dwExtraInfo)
{
INPUT input = new INPUT();
input.type = 1; //keyboard
input.ki.wVk = key;
input.ki.wScan = MapVirtualKey(key, 0);
input.ki.dwFlags = (int)flags;
SendInput(1, ref input, Marshal.SizeOf(input));
}