[RESOLVED] [2005] Recognizing null from byte string

[Bulldog]

I'm trying to convert a securestring to a string using the function below. However, the returned string always has one additional character appended which I think is a null. No matter what I do with "nothing", "vbnull", "dbnull" etc. this extra character is always present. I've even tried doing a .Replace on the final string but whatever it is remains.

The only fix I've found is to clip it off using a .Substring, but this is a nasty kludge.

Anyone see what I'm doing wrong?

Public Function SecureStringToString(ByVal str As System.Security.SecureString) As String
        Dim bstr As IntPtr = System.Runtime.InteropServices.Marshal.SecureStringToBSTR(str)
        Dim b As Byte = 1
        Dim i As Integer = 0
        Dim s As String = ""
        While Chr(b) <> Chr(0) 'I also tried IsNothing, IsNull, IsDBNull, = vbNull, = Nothing
            b = System.Runtime.InteropServices.Marshal.ReadByte(bstr, i)
            i += 2
            s += Chr(b)
        End While
        s = s.Substring(0, s.Length - 1) 'This line is the kludge
        System.Runtime.InteropServices.Marshal.FreeBSTR(bstr)
        Return s
    End Function