Is there an easy way to randomize a list in VB.NET?

Question

I have a list of type System.IO.FileInfo, and I would like to randomize the list. I thought I remember seeing something like list.randomize() a li

Answer 1

Build a Comparer:

Public Class Randomizer(Of T)
    Implements IComparer(Of T)

    ''// Ensures different instances are sorted in different orders
    Private Shared Salter As New Random() ''// only as random as your seed
    Private Salt As Integer
    Public Sub New()
        Salt = Salter.Next(Integer.MinValue, Integer.MaxValue)
    End Sub

    Private Shared sha As New SHA1CryptoServiceProvider()
    Private Function HashNSalt(ByVal x As Integer) As Integer
      Dim b() As Byte = sha.ComputeHash(BitConverter.GetBytes(x))
      Dim r As Integer = 0
      For i As Integer = 0 To b.Length - 1 Step 4
          r = r Xor BitConverter.ToInt32(b, i)
      Next

      Return r Xor Salt
    End Function

    Public Function Compare(x As T, y As T) As Integer _
        Implements IComparer(Of T).Compare

        Return HashNSalt(x.GetHashCode()).CompareTo(HashNSalt(y.GetHashCode()))
    End Function
End Class

Use it like this, assuming you mean a generic List(Of FileInfo):

list.Sort(New Randomizer(Of IO.FileInfo)())

You can also use a closure to make the random value 'sticky' and then just use linq's .OrderBy() on that (C# this time, because the VB lambda syntax is ugly):

list = list.OrderBy(a => Guid.NewGuid()).ToList();

Explained here, along with why it might not even be as fast as real shuffle:
http://www.codinghorror.com/blog/archives/001008.html?r=31644