C# Console - hide the input from console window while typing

Question

I'm using Console.ReadLineto read the input of the user. However, I want to hide/exclude the inputted text on the console screen while typing. For example, when the user writes "a", it writes "a" to the console and then I will have a variable with the value "a". However, I don't want "a" to be written on the console's output.

How can I do that?

Answer 1

Here is a short implementation. thx @ojblass for the idea

System.Console.Write("password: ");
string password = null;
while (true)
{
    var key = System.Console.ReadKey(true);
    if (key.Key == ConsoleKey.Enter)
        break;
    password += key.KeyChar;
}

Answer 2

Console.ReadKey(true) hides the user key. I do not believe Console.Read() offers such a capability. If necessary you can sit in a loop reading keys one at a time until enter is pressed. See this link for an example.

Answer 3

I created this method from the code in the answer by dataCore and the suggestion by m4tt1mus. I also added support for the backspace key.

private static string GetHiddenConsoleInput()
{
    StringBuilder input = new StringBuilder();
    while (true)
    {
        var key = Console.ReadKey(true);
        if (key.Key == ConsoleKey.Enter) break;
        if (key.Key == ConsoleKey.Backspace && input.Length > 0) input.Remove(input.Length - 1, 1);
        else if (key.Key != ConsoleKey.Backspace) input.Append(key.KeyChar);
    }
    return input.ToString();
}

Answer 4

I just changed the foreground colour to black while the password was being inputted. I a newbie so it's probably a bad idea but it worked for the challenge i was trying

Console.WriteLine("Welcome to our system. Please create a UserName");
        var userName = Console.ReadLine();
        Console.WriteLine("Now please create a password");
        Console.ForegroundColor = ConsoleColor.Black;
        var password = Console.ReadLine();
        Console.ForegroundColor = ConsoleColor.White;
        Console.WriteLine("Okay, let's get you logged in:");

Answer 5

private static string GetPassword()
    {
        StringBuilder input = new StringBuilder();
        while (true)
        {
            int x = Console.CursorLeft;
            int y = Console.CursorTop;
            ConsoleKeyInfo key = Console.ReadKey(true);
            if (key.Key == ConsoleKey.Enter)
            {
                Console.WriteLine();
                break;
            }
            if (key.Key == ConsoleKey.Backspace && input.Length > 0)
            {
                input.Remove(input.Length - 1, 1);
                Console.SetCursorPosition(x - 1, y);
                Console.Write(" ");
                Console.SetCursorPosition(x - 1, y);
            }
            else if (key.Key != ConsoleKey.Backspace)
            {
                input.Append(key.KeyChar);
                Console.Write("*");
            }
        }
        return input.ToString();
    }

Answer 6

For the sake of showing something different to the previous solutions and seeing as I love a good simple and dirty solution..

// Take input character
val = Console.ReadKey().KeyChar;
// Remove entered character from console
Console.Write("\b \b");

Obviously wrap in a loop and etc etc.

Very late to the party I know and a much less elegant solution compared with the rest but hopefully this might help someone in future.

Answer 7

If you just want to keep your neighbor from reading the password you can also play with the foreground color:

Console.Write("Enter root password:")
Dim oldColor As ConsoleColor = Console.ForegroundColor
Console.ForegroundColor = Console.BackgroundColor
rootPW = Console.ReadLine()
Console.ForegroundColor = oldColor

Answer 8

Improved version from @Fredrik Fjällström post: https://stackoverflow.com/a/59668053/2935383

His version is great because you can also see the cursor and set password-*** char if necessary. But what is still missing is the suppression of non-printable characters.

    public static string GetPassword()
    {
        StringBuilder input = new StringBuilder();
        while (true)
        {
            int x = Console.CursorLeft;
            int y = Console.CursorTop;
            ConsoleKeyInfo key = Console.ReadKey(true);
            if (key.Key == ConsoleKey.Enter)
            {
                Console.WriteLine();
                break;
            }
            if (key.Key == ConsoleKey.Backspace && input.Length > 0)
            {
                input.Remove(input.Length - 1, 1);
                Console.SetCursorPosition(x - 1, y);
                Console.Write(" ");
                Console.SetCursorPosition(x - 1, y);
            }
            else if( key.KeyChar < 32 || key.KeyChar > 126 )
            {
                Trace.WriteLine("Output suppressed: no key char"); //catch non-printable chars, e.g F1, CursorUp and so ...
            }
            else if (key.Key != ConsoleKey.Backspace)
            {
                input.Append(key.KeyChar);
                Console.Write("*");
            }
        }
        return input.ToString();
    }