Question

I’m doing basic random number generation using this Shared Function:

Public Shared Function RandomNumber(ByVal MaxNumber As Integer, Optional ByVal MinNumber As Integer = 0) As Integer

    'initialize random number generator
        Dim r As New Random(Date.Now.Ticks And &HFFFF)

        If MinNumber > MaxNumber Then
            Dim t As Integer = MinNumber
            MinNumber = MaxNumber
            MaxNumber = t
        End If

        Return r.Next(MinNumber, MaxNumber)

End Function

Called like this: dim x as integer = Random(2100000000)

Very simple, and the seed value comes straight from a MS example.

HERE’S THE PROBLEM: I’m getting duplicate numbers on occasion, but always created at times that are usually at least 5 or 10 minutes apart. I can see if I was calling the function multiple times per second or millisecond, because that’d kind of “breaks” the seed. But these are showing up at extended time spans. What else could be causing this?

Answer 1

Duplicate seed issue?

It might be better defining r as static so that it is initialised once when first invoked. Refer to this answer Random integer in VB.NET