Question

When building a Windows Console App in C#, is it possible to update lines in the console while waiting for a readline?

My current code is:

do
{
    Console.Clear();
    Console.WriteLine("RA:     " + scope.RightAscension);
    Console.WriteLine("Dec:    " + scope.Declination);
    Console.WriteLine("Status: " + scope.Slewing);
    System.Threading.Thread.Sleep(1000);
} while (true);

Answer 1

Yes. You can write to the Console from a separate thread while blocking on Console.ReadLine.

That being said, it’s going to cause confusion. In your case, you’ll clear out what the user is typing half-way through their line (via Console.Clear()), plus move the cursor position around dramatically.

---

Edit: Here’s an example that shows this:

namespace ConsoleApplication1
{
    using System;
    using System.Threading;

    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Starting");

            ThreadPool.QueueUserWorkItem(
                cb =>
                    {
                        int i = 1;
                        while (true)
                        {
                            Console.WriteLine("Background {0}", i++);
                            Thread.Sleep(1000);
                        }
                    });
            Console.WriteLine("Blocking");
            Console.WriteLine("Press Enter to exit...");
            Console.ReadLine();
        }
    }
}

If you run this, you’ll see the Console waits on ReadLine, but the background thread still prints.