Password in C# Console Application

thanks for you ansern!
i look for this for a long time

Hi Keith,

I'm puzzled by that as the backspace key should only work if at least one character has already been entered i.e. the length of the StringBuilder is greater than zero. If you try to key in backspace as the first character, it shouldn't have any effect.

Are you sure you've typed the code in correctly?

Hi Alan,

Your code is great !
But whenever I key in backspace as the first character, it will still take in.
I wonder if you have anyway to avoid that ?

I don't know whether there's an easier way but, if you have .NET 2.0 or 3.0, then this should work. You'll see that I've only allowed for the password to contain alphanumeric characters. All other characters are ignored except newline (to end the input) and backspace. In the case of the latter, I've recreated the functionality of the backspace key so that the user can delete the last key entered:

        using System.Text;   // as we're using StringBuilder

         .........

        Console.WriteLine("Pls key in your Login ID");
        loginid = Console.ReadLine();
        Console.WriteLine("Pls key in your Password");
        StringBuilder sb = new StringBuilder();
        char key;
        while ((key = Console.ReadKey(true).KeyChar) != '\r')  // continue until return pressed
        {
          if (key == '\b' && sb.Length > 0)  // backspace pressed after at least one char entered
          {
            Console.Write(key + " " + key);          
            sb = sb.Remove(sb.Length - 1, 1);
          }
          else if (Char.IsLetterOrDigit(key))
          {
            Console.Write("x");         
            sb = sb.Append(key);
          }
        }
        Console.WriteLine();
        password = sb.ToString();