using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {       

      Guid newID;

      Dictionary<Guid, int> dictionary= new Dictionary<Guid, int>(); 

      for (int value=0; value<100; value++) {   

        do newID = Guid.NewGuid();      

         while (! dictionary.TryAdd(newID, value));

      Console.WriteLine ("GUID: {0}", newID); 

      }

    }

}