Generate Random String (Letters & Numbers)

[Emcrank]

Here is a Sub to Generate a random string out of the letters A-Z and numbers 0-9, you can add more if you like.
ADDED: Feature so you cannot get the same string twice. (Even though it is very unlikly)

Private Sub GenerateString(ByVal Control As Control)
        Dim ListChars As New List(Of String)({"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", _
                              "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", _
                              "u", "v", "w", "x", "y", "z", _
                              "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", _
                              "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", _
                              "U", "V", "W", "X", "Y", "Z", _
                              "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"})
        Dim RandNumb As New Random
        Dim random1 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim random2 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim random3 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim random4 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim random5 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim random6 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim random7 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim random8 As String = ListChars(RandNumb.Next(0, ListChars.Count - 1))
        Dim History As New List(Of String)
        Dim GeneratedString As String = random1 & random2 & random3 & random4 & random5 & random6 & random7 & random8
        If History.Contains(GeneratedString) Then
            Do Until Not History.Contains(GeneratedString)
                random1 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                random2 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                random3 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                random4 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                random5 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                random6 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                random7 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                random8 = ListChars(RandNumb.Next(0, ListChars.Count - 1))
                GeneratedString = random1 & random2 & random3 & random4 & random5 & random6 & random7 & random8
            Loop
        End If
        Control.Text = GeneratedString
    End Sub

And to call this sub to put the generated string in a textbox just do,

GenerateString(TextBox1)