How to terminate a ReadLine()?

[blakemckenna]

I'm new to C# and learning to write a Console app. I'm catching on fairly quickly, however, I'm trying to create a little login app where the user is prompted to enter "Username:". When I enter a value for Username and press the enter key, the cursor just goes to the beginning of the line. What am I doing wrong?

Thanks,

        static void NewUser()
        {
            Console.WriteLine("\n\n");
            Console.Write("Enter Username: ");

            do
            {

                username = Console.ReadLine();

            } while (username != null);

            Console.Write("Enter Password: ");

            do
            {

                password = Console.ReadLine();

            } while (password != null);
        }

[jmcilhinney]

Your conditions are the wrong. You want to keep prompting the user as long as there is no value, so these:

        static void NewUser()
        {
            Console.WriteLine("\n\n");
            Console.Write("Enter Username: ");

            do
            {

                username = Console.ReadLine();

            } while (username != null);

            Console.Write("Enter Password: ");

            do
            {

                password = Console.ReadLine();

            } while (password != null);
        }

should be like this:

        static void NewUser()
        {
            Console.WriteLine("\n\n");
            Console.Write("Enter Username: ");

            do
            {

                username = Console.ReadLine();

            } while (username == null);

            Console.Write("Enter Password: ");

            do
            {

                password = Console.ReadLine();

            } while (password == null);
        }

Actually, comparing to null is useless regardless, because ReadLine will never return null. If the user enters no text then it will return an empty String, so that code should really be:

        static void NewUser()
        {
            Console.WriteLine("\n\n");
            Console.Write("Enter Username: ");

            do
            {

                username = Console.ReadLine();

            } while (username == string.Empty);

            Console.Write("Enter Password: ");

            do
            {

                password = Console.ReadLine();

            } while (password == string.Empty);
        }

[blakemckenna]

jmc,

Thanks for your answer. It works, but I find that when I enter a value for the Username...I have to hit the <enter> key twice in order to get prompted to enter the Password.

[jmcilhinney]

I just used this exact code and it worked fine for me:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            NewUser();
            Console.ReadLine();
        }
 
        private static string username;
        private static string password;
 
        static void NewUser()
        {
            Console.WriteLine("\n\n");
            Console.Write("Enter Username: ");
 
            do
            {
 
                username = Console.ReadLine();
 
            } while (username == string.Empty);
 
            Console.Write("Enter Password: ");
 
            do
            {
 
                password = Console.ReadLine();
 
            } while (password == string.Empty);
        }
    }
}

[blakemckenna]

I copied that same code into my app and it still didn't work. I have included all of the code (which is pretty little). Perhaps there is something that changing the ReadLine in how it acts...just a guess.

using System;
using System.Collections.Generic;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)

        {
            ConsoleKeyInfo keyInput;
            // Prevent example from ending if CTL+C is pressed.
            Console.TreatControlCAsInput = true;

            Console.WriteLine("\n");
            Console.WriteLine("                             Select an Option\n");
            Console.Write("   (N)ew User or (L)ogin or (T)ransaction or Transaction (H)istory or Esc: ");

            keyInput = Console.ReadKey(true);

            switch (keyInput.Key)
            {
                case ConsoleKey.L:
                    LogIn();
                    break;
                case ConsoleKey.N:
                    EnterUserInfo();
                    break;
                default:
                    break;
            }
        }

        static string username;
        static string password;

        //
        //=============================================================================================
        //
         static void EnterUserInfo()
        {
            Console.Write("\n\n" + "   Enter Username: ");

            do
            {
                username = Console.ReadLine();

            } while (username == string.Empty);

            Console.Write("\n" + "   Enter Password: ");

            do
            {
                password = Console.ReadLine();

            } while (password == string.Empty);
        }
        //
        //=============================================================================================
        //
        static void LogIn()
        {

        }
        //
        //=============================================================================================
        //
        static void TranslateInput()
        {

        }
    }
}

[jmcilhinney]

I tried your code and it behaved as you said. I commented out this line:

Console.TreatControlCAsInput = true;

and it worked as expected.

https://stackoverflow.com/questions/...-is-this-a-bug

[blakemckenna]

Thanks jmc...appreciate the help!