C# hold key in a game application

c++fullscreenkeykeyup

I'm trying to make a C# application, which is going to control a game. That I'm trying to do is for example: Hold key A for 150ms, Hold left arrow for 500ms and so on.
I was searching a lot and I found the following code. My program firstly target the game and then holding the keys.

I'm holding the keys this way:

Keyboard.HoldKey(Keys.Left);
Thread.sleep(500);
Keyboard.ReleaseKey(Keys.Left);

Here is the Keyboard class:

public class Keyboard
 {
    public Keyboard()
    {
    }

    [StructLayout(LayoutKind.Explicit, Size = 28)]
    public struct Input
    {
        [FieldOffset(0)]
        public uint type;
        [FieldOffset(4)]
        public KeyboardInput ki;
    }

    public struct KeyboardInput
    {
        public ushort wVk;
        public ushort wScan;
        public uint dwFlags;
        public long time;
        public uint dwExtraInfo;
    }

    const int KEYEVENTF_KEYUP = 0x0002;
    const int INPUT_KEYBOARD = 1;

    [DllImport("user32.dll")]
    public static extern int SendInput(uint cInputs, ref Input inputs, int cbSize);

    [DllImport("user32.dll")]
    static extern short GetKeyState(int nVirtKey);

    [DllImport("user32.dll")]
    static extern ushort MapVirtualKey(int wCode, int wMapType);


    public static bool IsKeyDown(Keys key)
    {
        return (GetKeyState((int)key) & -128) == -128;
    }

    public static void HoldKey(Keys vk)
    {
        ushort nScan = MapVirtualKey((ushort)vk, 0);

        Input input = new Input();
        input.type = INPUT_KEYBOARD;
        input.ki.wVk = (ushort)vk;
        input.ki.wScan = nScan;
        input.ki.dwFlags = 0;
        input.ki.time = 0;
        input.ki.dwExtraInfo = 0;
        SendInput(1, ref input, Marshal.SizeOf(input)).ToString();
    }

    public static void ReleaseKey(Keys vk)
    {
        ushort nScan = MapVirtualKey((ushort)vk, 0);

        Input input = new Input();
        input.type = INPUT_KEYBOARD;
        input.ki.wVk = (ushort)vk;
        input.ki.wScan = nScan;
        input.ki.dwFlags = KEYEVENTF_KEYUP;
        input.ki.time = 0;
        input.ki.dwExtraInfo = 0;
        SendInput(1, ref input, Marshal.SizeOf(input));
    }

    public static void PressKey(Keys vk)
    {
        HoldKey(vk);
        ReleaseKey(vk);
    }
}

and its working in notepad/browser etc, but it IS NOT working in any game, no matter fullscreen or window mode.
Can you help me to figure out how I can hold keys in full screen apps/games?
Thanks!

Best Solution

"Hold key A for 150ms, Hold left arrow for 500ms"

See if this works:

        Keyboard.HoldKey((byte)Keys.A, 150);
        Keyboard.HoldKey((byte)Keys.Left, 500);

Using:

public class Keyboard
{
    [DllImport("user32.dll", SetLastError = true)]
    static extern void keybd_event(byte bVk, byte bScan, int dwFlags, int dwExtraInfo);

    const int KEY_DOWN_EVENT = 0x0001; //Key down flag
    const int KEY_UP_EVENT = 0x0002; //Key up flag

    public static void HoldKey(byte key, int duration)
    {
        int totalDuration = 0;
        while (totalDuration < duration)
        {
            keybd_event(key, 0, KEY_DOWN_EVENT, 0);
            keybd_event(key, 0, KEY_UP_EVENT, 0);
            System.Threading.Thread.Sleep(PauseBetweenStrokes);
            totalDuration += PauseBetweenStrokes;
        }
    }
}