Creating a Alpha numeric string in VB.NET

=====Generating a Alpha numeric Random number====

If System.String.Compare(txtPassword.Value, "", True) = 0 Then

Dim iNumChars As Integer

iNumChars = 5

txtPassword.Value = u_logic.RandomString(iNumChars)

End If

'=====Ends Here===================================



Public Function RandomString(ByVal iLength As Integer) As String

Dim iZero, iNine, iA, iZ, iCount, iRandNum As Integer

Dim sRandomString As String

' we'll need random characters, so a Random object

' should probably be created...

Dim rRandom As New Random(System.DateTime.Now.Millisecond)

' convert characters into their integer equivalents (their ASCII values)

iZero = Asc("0")

iNine = Asc("9")

iA = Asc("A")

iZ = Asc("Z")

' initialize our return string for use in the following loop

sRandomString = String.Empty

' now we loop as many times as is necessary to build the string

' length we want

While (iCount < iLength)

' we fetch a random number between our high and low values

iRandNum = rRandom.Next(iZero, iZ)

' here's the cool part: we inspect the value of the random number,

' and if it matches one of the legal values that we've decided upon,

' we convert the number to a character and add it to our string

If (((iRandNum >= iZero) And (iRandNum <= iNine) _

Or (iRandNum >= iA) And (iRandNum <= iZ))) Then

sRandomString = sRandomString + Chr(iRandNum)

iCount = iCount + 1

End If

End While

' finally, our random character string should be built, so we return it

RandomString = sRandomString

End Function