C# simulate mouse and keyboard events

This is achieved by calling windows API functions.
Also see
reference.

using System.Runtime.InteropServices;

public class Form1 : System.Windows.Forms.Form {
  public enum VK : ushort
  {
   SHIFT        = 0x10,
   CONTROL      = 0x11,
   MENU         = 0x12,
   ESCAPE       = 0x1B,
   BACK         = 0x08,
   TAB          = 0x09,
   RETURN       = 0x0D,
   PRIOR        = 0x21,
   NEXT         = 0x22,
   END          = 0x23,
   HOME         = 0x24,
   LEFT         = 0x25,
   UP           = 0x26,
   RIGHT        = 0x27,
   DOWN         = 0x28,
   SELECT       = 0x29,
   PRINT        = 0x2A,
   EXECUTE      = 0x2B,
   SNAPSHOT     = 0x2C,
   INSERT       = 0x2D,
   DELETE       = 0x2E,
   HELP         = 0x2F,
   NUMPAD0      = 0x60,
   NUMPAD1      = 0x61,
   NUMPAD2      = 0x62,
   NUMPAD3      = 0x63,
   NUMPAD4      = 0x64,
   NUMPAD5      = 0x65,
   NUMPAD6      = 0x66,
   NUMPAD7      = 0x67,
   NUMPAD8      = 0x68,
   NUMPAD9      = 0x69,
   MULTIPLY     = 0x6A,
   ADD          = 0x6B,
   SEPARATOR    = 0x6C,
   SUBTRACT     = 0x6D,
   DECIMAL      = 0x6E,
   DIVIDE       = 0x6F,
   F1           = 0x70,
   F2           = 0x71,
   F3           = 0x72,
   F4           = 0x73,
   F5           = 0x74,
   F6           = 0x75,
   F7           = 0x76,
   F8           = 0x77,
   F9           = 0x78,
   F10          = 0x79,
   F11          = 0x7A,
   F12          = 0x7B,
   OEM_1        = 0xBA,   // ',:' for US
   OEM_PLUS     = 0xBB,   // '+' any country
   OEM_COMMA    = 0xBC,   // ',' any country
   OEM_MINUS    = 0xBD,   // '-' any country
   OEM_PERIOD   = 0xBE,   // '.' any country
   OEM_2        = 0xBF,   // '/?' for US
   OEM_3        = 0xC0,   // '`~' for US
   MEDIA_NEXT_TRACK     = 0xB0,
   MEDIA_PREV_TRACK     = 0xB1,
   MEDIA_STOP           = 0xB2,
   MEDIA_PLAY_PAUSE     = 0xB3,
   LWIN       =0x5B,
   RWIN       =0x5C
  }

  #region Dll Imports

  [StructLayout(LayoutKind.Sequential)]
   struct MOUSEINPUT
  {
   public int dx;
   public int dy;
   public uint mouseData;
   public uint dwFlags;
   public uint time;
   public IntPtr dwExtraInfo;
  }

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

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

  [StructLayout(LayoutKind.Explicit)]
   struct INPUT
  {
   [FieldOffset(0)]
   public int type;
   [FieldOffset(4)] 
   public MOUSEINPUT mi;
   [FieldOffset(4)] 
   public KEYBDINPUT ki;
   [FieldOffset(4)] 
   public HARDWAREINPUT hi;
  }

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

  const int INPUT_MOUSE          = 0;
  const int INPUT_KEYBOARD       = 1;
  const int INPUT_HARDWARE       = 2;
  const uint KEYEVENTF_EXTENDEDKEY   = 0x0001;
  const uint KEYEVENTF_KEYUP     = 0x0002;
  const uint KEYEVENTF_UNICODE       = 0x0004;
  const uint KEYEVENTF_SCANCODE      = 0x0008;
  const uint XBUTTON1        = 0x0001;
  const uint XBUTTON2        = 0x0002;
  const uint MOUSEEVENTF_MOVE    = 0x0001;
  const uint MOUSEEVENTF_LEFTDOWN    = 0x0002;
  const uint MOUSEEVENTF_LEFTUP      = 0x0004;
  const uint MOUSEEVENTF_RIGHTDOWN   = 0x0008;
  const uint MOUSEEVENTF_RIGHTUP     = 0x0010;
  const uint MOUSEEVENTF_MIDDLEDOWN  = 0x0020;
  const uint MOUSEEVENTF_MIDDLEUP    = 0x0040;
  const uint MOUSEEVENTF_XDOWN       = 0x0080;
  const uint MOUSEEVENTF_XUP     = 0x0100;
  const uint MOUSEEVENTF_WHEEL       = 0x0800;
  const uint MOUSEEVENTF_VIRTUALDESK = 0x4000;
  const uint MOUSEEVENTF_ABSOLUTE    = 0x8000;


  private MOUSEINPUT createMouseInput(int x, int y, uint data, uint t, uint flag) {
   MOUSEINPUT mi = new MOUSEINPUT();
   mi.dx = x;
   mi.dy = y;
   mi.mouseData = data;
   mi.time = t;
   //mi.dwFlags = MOUSEEVENTF_ABSOLUTE| MOUSEEVENTF_MOVE;
   mi.dwFlags = flag;
   return mi;
  }

  private KEYBDINPUT createKeybdInput(short wVK, uint flag) 
  {
   KEYBDINPUT i = new KEYBDINPUT();
   i.wVk = (ushort) wVK;
   i.wScan = 0;
   i.time = 0;
   i.dwExtraInfo = IntPtr.Zero;
   i.dwFlags = flag; 
   return i;
  }

  private short getCVal(char c) {
   if (c >= 'a' && c <= 'z') return c - 'a' + 0x61;
   else if (c >= '0' && c <= '9') return c - '0' + 0x30;
   else if (c == '-') return 0x6D; // Note it's NOT 0x2D as in ASCII code!
   else return 0; // default
  }

  /// 

  /// Each time first move the upper left corner, then move from there.
  /// x, y: pixel value of position.
  /// 
  private void sim_mov(int x, int y) {
   INPUT[] inp = new INPUT[2];
   inp[0].type = INPUT_MOUSE;
   inp[0].mi = createMouseInput(0, 0, 0, 0, MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_MOVE);
   inp[1].type = INPUT_MOUSE;
   inp[1].mi = createMouseInput(x, y, 0, 0, MOUSEEVENTF_MOVE); 
   SendInput((uint)inp.Length, inp, Marshal.SizeOf(inp[0].GetType()));
  }

  private void sim_click() 
  {
   INPUT[] inp = new INPUT[2];
   inp[0].type = INPUT_MOUSE;
   inp[0].mi = createMouseInput(0, 0, 0, 0, MOUSEEVENTF_LEFTDOWN);
   inp[1].type = INPUT_MOUSE;
   inp[1].mi = createMouseInput(0, 0, 0, 0, MOUSEEVENTF_LEFTUP);
   SendInput((uint)inp.Length, inp, Marshal.SizeOf(inp[0].GetType()));
  }

  private void sim_type(string txt) 
  {
   int i, len;
   char[] c_array;
   short c;
   INPUT[] inp;

   if (txt == null || txt.Length == 0) return;

   c_array = txt.ToCharArray();
   len = c_array.Length;
   inp = new INPUT[2];

   for (i = 0; i < len; i ++) 
   {
    c = getCVal(txt[i]); 
    
    inp[0].type = INPUT_KEYBOARD;
    inp[0].ki = createKeybdInput(c, 0);
    inp[1].type = INPUT_KEYBOARD;
    inp[1].ki = createKeybdInput(c, KEYEVENTF_KEYUP);
    
    SendInput((uint)inp.Length, inp, Marshal.SizeOf(inp[0].GetType()));
   }
  }

  private void sim_actions() {
   sim_mov(x0, y0);
   sim_click();
  }

  public Form1() {
    InitializeComponent();
    //sim_actions();
  }

  [STAThread]
  static void Main() {
    Application.Run(new Form1());
  }
}