C Send Input Simulate Mouse Click to Focus Window

Code

public const int INPUT_MOUSE = 0;

public const int INPUT_KEYBOARD = 1;

public const int INPUT_HARDWARE = 2;



[Flags]

public enum MOUSEEVENTF : uint

{

MOUSEEVENTF_ABSOLUTE = 0x8000,

MOUSEEVENTF_LEFTDOWN = 0x0002,

MOUSEEVENTF_LEFTUP = 0x0004,

MOUSEEVENTF_MIDDLEDOWN = 0x0020,

MOUSEEVENTF_MIDDLEUP = 0x0040,

MOUSEEVENTF_MOVE = 0x0001,

MOUSEEVENTF_RIGHTDOWN = 0x0008,

MOUSEEVENTF_RIGHTUP = 0x0010,

MOUSEEVENTF_XDOWN = 0x0080,

MOUSEEVENTF_XUP = 0x0100,

MOUSEEVENTF_WHEEL = 0x0800,

MOUSEEVENTF_HWHEEL = 0x01000,

}



[StructLayout(LayoutKind.Sequential)]

internal struct MOUSEINPUT

{

    internal int dx;

    internal int dy;

    internal int mouseData;

    internal MOUSEEVENTF dwFlags;

    internal uint time;

    internal UIntPtr dwExtraInfo;

}



[StructLayout(LayoutKind.Sequential)]

public struct KEYBDINPUT

{

    public ushort wVk;

    public ushort wScan;

    public uint dwFlags;

    public uint time;

    public IntPtr dwExtraInfo;

}



[StructLayout(LayoutKind.Sequential)]

public struct HARDWAREINPUT

{

    uint uMsg;

    ushort wParamL;

    ushort wParamH;

}



[StructLayout(LayoutKind.Explicit)]

public struct INPUT

{

    [FieldOffset(0)]

    public int type;

    [FieldOffset(4)] //*

    public MOUSEINPUT mi;

    [FieldOffset(4)] //*

    public KEYBDINPUT ki;

    [FieldOffset(4)] //*

    public HARDWAREINPUT hi;

}

Code

[DllImport("user32.dll")]

internal static extern uint SendInput(uint nInputs, [MarshalAs(UnmanagedType.LPArray), In] INPUT[] pInputs, int cbSize);



[DllImport("user32.dll")]

public static extern IntPtr SetFocus(IntPtr hWnd);



Process proc = Process.GetProcessesByName("ac_client")[0];



uint hwnd = (uint)proc.MainWindowHandle.ToInt32();



INPUT[] mInput = new INPUT[1];

mInput[0].type = INPUT_MOUSE;

mInput[0].mi.dwFlags = MOUSEEVENTF.MOUSEEVENTF_LEFTDOWN;



SetFocus(proc.MainWindowHandle);



SendInput(hwnd, mInput, System.Runtime.InteropServices.Marshal.SizeOf(mInput[0]));