RemoteView/NativeMethods.cs


using System;
using System.Net;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace RemoteView
{

    /// <summary>
    /// This class is heavily based on source code presented as an answer at
    /// http://stackoverflow.com/questions/8021954/sendinput-doesnt-perform-click-mouse-button-unless-i-move-cursor
    /// </summary>
    class NativeMethods
    {
        /// <summary>
        /// Don't allow instatiation of this class
        /// </summary>
        private NativeMethods()
        {
        }

        enum SystemMetric
        {
            SM_CXSCREEN = 0,
            SM_CYSCREEN = 1,
        }
        
        [DllImport("user32.dll")]
        static extern int GetSystemMetrics(SystemMetric smIndex);

        [DllImport("user32.dll", SetLastError = true)]
        static extern uint SendInput(uint nInputs, ref INPUT pInputs, int cbSize);

        [StructLayout(LayoutKind.Sequential)]
        public struct HARDWAREINPUT
        {
            public int uMsg;
            public short wParamL;
            public short wParamH;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct KEYBDINPUT
        {
            public ushort wVk;
            public ushort wScan;
            public uint dwFlags;
            public uint time;
            public IntPtr dwExtraInfo;
        }

        [StructLayout(LayoutKind.Explicit)]
        public struct MouseKeybdhardwareInputUnion
        {
            [FieldOffset(0)]
            public MouseInputData mi;

            [FieldOffset(0)]
            public KEYBDINPUT ki;

            [FieldOffset(0)]
            public HARDWAREINPUT hi;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct INPUT
        {
            public SendInputEventType type;
            public MouseKeybdhardwareInputUnion mkhi;
        }

        [Flags]
        public enum MouseEventFlags : uint
        {
            MOUSEEVENTF_MOVE = 0x0001,
            MOUSEEVENTF_LEFTDOWN = 0x0002,
            MOUSEEVENTF_LEFTUP = 0x0004,
            MOUSEEVENTF_RIGHTDOWN = 0x0008,
            MOUSEEVENTF_RIGHTUP = 0x0010,
            MOUSEEVENTF_MIDDLEDOWN = 0x0020,
            MOUSEEVENTF_MIDDLEUP = 0x0040,
            MOUSEEVENTF_XDOWN = 0x0080,
            MOUSEEVENTF_XUP = 0x0100,
            MOUSEEVENTF_WHEEL = 0x0800,
            MOUSEEVENTF_VIRTUALDESK = 0x4000,
            MOUSEEVENTF_ABSOLUTE = 0x8000
        }

        public enum SendInputEventType : int
        {
            InputMouse,
            InputKeyboard,
            InputHardware
        }

        public struct MouseInputData
        {
            public int dx;
            public int dy;
            public uint mouseData;
            public MouseEventFlags dwFlags;
            public uint time;
            public IntPtr dwExtraInfo;
        }

        public static int CalculateAbsoluteCoordinateX(int x)
        {
            return (x * 65536) / GetSystemMetrics(SystemMetric.SM_CXSCREEN);
        }

        public static int CalculateAbsoluteCoordinateY(int y)
        {
            return (y * 65536) / GetSystemMetrics(SystemMetric.SM_CYSCREEN);
        }

        public static void LeftMouseButton(MouseEventFlags mouseEventFlags, int x, int y)
        {
            INPUT mouseInput = new INPUT();
            mouseInput.type = SendInputEventType.InputMouse;
            mouseInput.mkhi.mi.dx = CalculateAbsoluteCoordinateX(x);
            mouseInput.mkhi.mi.dy = CalculateAbsoluteCoordinateY(y);
            mouseInput.mkhi.mi.mouseData = 0;

            mouseInput.mkhi.mi.dwFlags = MouseEventFlags.MOUSEEVENTF_MOVE | MouseEventFlags.MOUSEEVENTF_ABSOLUTE;
            SendInput(1, ref mouseInput, Marshal.SizeOf(new INPUT()));

            mouseInput.mkhi.mi.dwFlags = mouseEventFlags;
            SendInput(1, ref mouseInput, Marshal.SizeOf(new INPUT()));
        }

        public static void ClickRightMouseButton(int x, int y)
        {
            INPUT mouseInput = new INPUT();
            mouseInput.type = SendInputEventType.InputMouse;
            mouseInput.mkhi.mi.dx = CalculateAbsoluteCoordinateX(x);
            mouseInput.mkhi.mi.dy = CalculateAbsoluteCoordinateY(y);
            mouseInput.mkhi.mi.mouseData = 0;

            mouseInput.mkhi.mi.dwFlags = MouseEventFlags.MOUSEEVENTF_MOVE | MouseEventFlags.MOUSEEVENTF_ABSOLUTE;
            SendInput(1, ref mouseInput, Marshal.SizeOf(new INPUT()));

            mouseInput.mkhi.mi.dwFlags = MouseEventFlags.MOUSEEVENTF_RIGHTDOWN;
            SendInput(1, ref mouseInput, Marshal.SizeOf(new INPUT()));

            mouseInput.mkhi.mi.dwFlags = MouseEventFlags.MOUSEEVENTF_RIGHTUP;
            SendInput(1, ref mouseInput, Marshal.SizeOf(new INPUT()));
        }

        public static void MoveMouse(int x, int y)
        {
            INPUT mouseInput = new INPUT();
            mouseInput.type = SendInputEventType.InputMouse;
            mouseInput.mkhi.mi.dx = CalculateAbsoluteCoordinateX(x);
            mouseInput.mkhi.mi.dy = CalculateAbsoluteCoordinateY(y);
            mouseInput.mkhi.mi.mouseData = 0;

            mouseInput.mkhi.mi.dwFlags = MouseEventFlags.MOUSEEVENTF_MOVE | MouseEventFlags.MOUSEEVENTF_ABSOLUTE;
            SendInput(1, ref mouseInput, Marshal.SizeOf(new INPUT()));

        }
    }
}