C# arrow key input for a console app

Question

I have a simple console app written in C#. I want to be able to detect arrow key presses, so I can allow the user to steer. How do I detect keydown/keyup events with a con

Answer 1

I have the same issue that you and I found, here, an interesting post using tasks. The original post can be found here: C# Console Application - How do I always read input from the console?

I have to emulate a PWM output through a Raspberry GPIO (using mono C#) to test a LCD backlight. With two simple keys I wanted to change the duty cycle (up/down) and an extra key to stop the program.

I tried this (variables):

static ConsoleKeyInfo key = new ConsoleKeyInfo();
static int counter = 0;
static int duty = 5; // Starts in 50%

Main program:

static void Main(string[] args)
{
// cancellation by keyboard string
    CancellationTokenSource cts = new CancellationTokenSource();
    // thread that listens for keyboard input
    var kbTask = Task.Run(() =>
    {
        while (true)
        {
            key = Console.ReadKey(true);
            if (key.KeyChar == 'x' || key.KeyChar == 'X')
            {
                cts.Cancel();
                break;
            }
            else if (key.KeyChar == 'W' || key.KeyChar == 'w')
            {
                if (duty < 10)
                    duty++;
                //Console.WriteLine("\tIncrementa Ciclo");
                //mainAppState = StateMachineMainApp.State.TIMER;
                //break;
            }
            else if (key.KeyChar == 'S' || key.KeyChar == 's')
            {
                if (duty > 0)
                    duty--;
                //Console.WriteLine("\tDecrementa Ciclo");
                //mainAppState = StateMachineMainApp.State.TIMER;
                // break;
            }
        }
    });

    // thread that performs main work
    Task.Run(() => DoWork(), cts.Token);

    string OsVersion = Environment.OSVersion.ToString();
    Console.WriteLine("Sistema operativo: {0}", OsVersion);
    Console.WriteLine("Menú de Progama:");
    Console.WriteLine(" W. Aumentar ciclo útil");
    Console.WriteLine(" S. Disminuir ciclo útil");
    Console.WriteLine(" X. Salir del programa");

    Console.WriteLine();
    // keep Console running until cancellation token is invoked
    kbTask.Wait();
}

static void DoWork()
{
    while (true)
    {
        Thread.Sleep(50);
        if (counter < 10)
        {
            if (counter < duty)
                Console.Write("─");
                //Console.WriteLine(counter + " - ON");
            else
                Console.Write("_");
                //Console.WriteLine(counter + " - OFF");
            counter++;
        }
        else
        {
            counter = 0;
        }
    }
}

When it's needed to increment the duty cycle, pressing 'W' key makes that the main task changes the duty cycle variable (duty); the same thing with 'S' key to decrement. The program finishes when 'X' key is pressed.