VS 2013 - Generate Random String

[ByteKnight]

I wrote this code pretty quickly. I never had any formal coding training so please forgive the less than perfect coding style. It is fully function and allows the paramters of Length, and using both upper/lower case.

Private Function GenerateString(ByVal CharCount As Long, ByVal UseLCase As Boolean, ByVal CharSetToUse as Integer)
        Dim rnd, rnd2 As New Random
        Dim AZ As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
        Dim Nums As String = "1234567890"
        Dim Special As String = "~!@#$%^&*()_+{}[]"
        Dim CharsToUse As New StringBuilder
        Dim NewString As New StringBuilder
        Select Case CharSetToUse
            Case 0
                CharsToUse.Append(AZ)
            Case 1
                CharsToUse.Append(AZ)
                CharsToUse.Append(Nums)
            Case 2
                CharsToUse.Append(AZ)
                CharsToUse.Append(Nums)
                CharsToUse.Append(Special)
        End Select
        For i = 0 To CharCount - 1
            Dim chars As String = rnd.Next(0, CharsToUse.Length)
            Dim ULCase As Integer = rnd2.Next(1, 3)
            Console.WriteLine(ULCase)
            If UseLCase = True Then
                Select Case ULCase
                    Case 1
                        NewString.Append(LCase(CharsToUse.Chars(chars)))
                    Case 2
                        NewString.Append(UCase(CharsToUse.Chars(chars)))
                End Select
            Else
                NewString.Append(CharsToUse.Chars(chars))
            End If


        Next
        Return NewString.ToString

[passel]

The code looks to be tied to (i.e. requires) a combobox named cmbCharsToUse.
That enumeration should probably be passed as a parameter to the Function, rather than hardcoded to a control outside the function.
Also, there is no need to have two Random objects.

[ByteKnight]

Thank you for pointing this out. I have editted the code. I added another parameter than can be specificed as 0, 1, or 2.