public static extern int GetRawInputData(IntPtr hRawInput, RawInputCommand uiCommand, out RAWINPUT pData, ref int pcbSize, int cbSizeHeader);

    public static extern int GetRawInputData(IntPtr hRawInput, RawInputCommand uiCommand, byte[] pData, ref int pcbSize, int cbSizeHeader);

            outSize = Win32API.GetRawInputData(m.LParam, RawInputCommand.Input, out input, ref size, Marshal.SizeOf(typeof(RAWINPUTHEADER)));

    public enum RawInputCommand

Enum RawInputCommand