C# DirectInput SendInput Doesn't affect to game

Question

I need some help about DirectInput, I'll tell what i am trying to do. I want to do my program sends key combinations to a game when i press only one key. Examp.: I'll press "r" and it will pres "1","3","2","4" keys. I found some codes from here. But they didn't worked exactly.

    public static void Send_Key_Hold(short Keycode)
    {
        INPUT[] InputData = new INPUT[1];
        InputData[0].type = 1;
        InputData[0].ki.wScan = Keycode;
        InputData[0].ki.dwFlags = (int)(KEYEVENTF_SCANCODE);

        SendInput(1, InputData, Marshal.SizeOf(InputData[0]));
    }
    public static void Send_Key_Release(short Keycode)
    {
        INPUT[] InputData = new INPUT[1];
        InputData[0].type = 1;
        InputData[0].ki.wScan = Keycode;
        InputData[0].ki.dwFlags = (int)(KEYEVENTF_KEYUP | KEYEVENTF_SCANCODE);

        SendInput(1, InputData, Marshal.SizeOf(InputData[0]));
    }

Here is my code and my question: When I'm using Send_Key_Hold only it presses one key in the game and other combination keys not pressed because first key is holded i think. When I'm using Send_Key_Hold and Send_Key_Release together it doesn't press any buttons on game. But on desktop (i mean anyother application not game) it presses the key.

Answer 1

I've found this example on internet. Tested it on my own when I tried to do the same thing as you are trying now.

[Flags]
private enum InputType
{
    Mouse = 0,
    Keyboard = 1,
    Hardware = 2
}

[Flags]
private enum KeyEventF
{
    KeyDown = 0x0000,
    ExtendedKey = 0x0001,
    KeyUp = 0x0002,
    Unicode = 0x0004,
    Scancode = 0x0008,
}

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

[DllImport("user32.dll")]
private static extern IntPtr GetMessageExtraInfo();

public static void SendKey(ushort key)
{
    Input[] inputs =
    {
        new Input
        {
            type = (int) InputType.Keyboard,
            u = new InputUnion
            {
                ki = new KeyboardInput
                {
                    wVk = 0,
                    wScan = key,
                    dwFlags = (uint) (KeyEventF.KeyDown | KeyEventF.Scancode),
                    dwExtraInfo = GetMessageExtraInfo()
                }
            }
        }
    };

    SendInput((uint) inputs.Length, inputs, Marshal.SizeOf(typeof (Input)));
}

private struct Input
{
    public int type;
    public InputUnion u;
}

[StructLayout(LayoutKind.Explicit)]
private struct InputUnion
{
    [FieldOffset(0)] public readonly MouseInput mi;
    [FieldOffset(0)] public KeyboardInput ki;
    [FieldOffset(0)] public readonly HardwareInput hi;
}

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

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

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

Now use SendKey(0x14) to send your T key to the active window (or game).

Note: You need KeyEventF.Scancode as your flag or the wScan property will be ignored!