using System; public class Test { static DateTime RandomDay() { DateTime start = new DateTime(1995, 1, 1); Random gen = new Random(); int range = (DateTime.Today - start).Days; return start.AddDays(gen.Next(range)); } public static void Main() { var randomDate = RandomDay(); TimeSpan TimeDifference = DateTime.Now - randomDate; string result = string.Format(@"{0:hh\:mm\:ss}", TimeDifference); Console.WriteLine(result); DateTime dt = DateTime.MinValue.Add(TimeDifference); result = dt.ToString(@"hh\:mm\:ss"); Console.WriteLine(result); } }