[VB.Net 2005]Mask Password in Console Application

Normally in a Winform application, a TextBox is used for users to type in their password and it's very easy to mask the typed in password by setting the TextBox.PasswordChar property to whatever character you want to used as the mask. However, in a console application, it's not so simple. For each keystroke, we have to read the ConsoleKeyInfo, save the character, wipe out what the use just typed on screen to replace it with a password mask character.

This little function does just that.

vb.net Code:

Private Function GetPassword(Optional ByVal passwordMask As Char = "*"c) As String
        Dim pwd As String = String.Empty
        Dim sb As New System.Text.StringBuilder()
        Dim cki As ConsoleKeyInfo = Nothing
 
        'Get the password
        Console.Write("Enter password: ")
        While (True)
            While Console.KeyAvailable() = False
                System.Threading.Thread.Sleep(50)
            End While
            cki = Console.ReadKey(True)
            If cki.Key = ConsoleKey.Enter Then
                Console.WriteLine()
                Exit While
            ElseIf cki.Key = ConsoleKey.Backspace Then
                If sb.Length > 0 Then
                    sb.Length -= 1
                    Console.Write(ChrW(8) & ChrW(32) & ChrW(8))
                End If
                Continue While
            ElseIf Asc(cki.KeyChar) < 32 OrElse Asc(cki.KeyChar) > 126 Then
                Continue While
            End If
            sb.Append(cki.KeyChar)
            Console.Write(passwordMask)
        End While
        pwd = sb.ToString()
        Return pwd
    End Function