Hi there. I've build a random string generator but I'm having a problem whereby if I call the function multiple times say in a Page_Load method, the function returns the same string twice.

here's the code

    ''' <summary>'
    ''' Generates a Random String'
    ''' </summary>'
    ''' <param name="n">number of characters the method should generate</param>'
    ''' <param name="UseSpecial">should the method include special characters? IE: # ,$, !, etc.</param>'
    ''' <param name="SpecialOnly">should the method include only the special characters and excludes alpha numeric</param>'
    ''' <returns>a random string n characters long</returns>'
    Public Function GenerateRandom(ByVal n As Integer, Optional ByVal UseSpecial As Boolean = True, Optional ByVal SpecialOnly As Boolean = False) As String

        Dim chars As String() ' a character array to use when generating a random string'
        Dim ichars As Integer = 74 'number of characters to use out of the chars string'
        Dim schars As Integer = 0 ' number of characters to skip out of the characters string'

        chars = { _
         "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", _
         "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", "!", "@", "#", "$", _
         "%", "^", "&", "*", "(", ")", _
         "-", "+"}


        If Not UseSpecial Then ichars = 62 ' only use the alpha numeric characters out of "char"'
        If SpecialOnly Then schars = 62 : ichars = 74 ' skip the alpha numeric characters out of "char"'

        Dim rnd As New Random()
        Dim random As String = String.Empty
        Dim i As Integer = 0
        While i < n
            random += chars(rnd.[Next](schars, ichars))
            System.Math.Max(System.Threading.Interlocked.Increment(i), i - 1)
        End While
        rnd = Nothing
        Return random
    End Function

but if I call something like this

    Dim str1 As String = GenerateRandom(5) 
    Dim str2 As String = GenerateRandom(5) 

the response will be something like this

g*3Jq
g*3Jq

and the second time I call it, it will be

3QM0$
3QM0$

What am I missing? I'd like every random string to be generated as unique.