public static Guid GenerateComb()
{
var guidArray = Guid.NewGuid().ToByteArray();
var now = DateTime.UtcNow;
// Get the days and milliseconds which will be used to build the byte string
var days = new TimeSpan(now.Ticks - _baseDateTicks);
var msecs = now.TimeOfDay;
// Convert to a byte array
// Note that SQL Server is accurate to 1/300th of a millisecond so we divide by 3.333333
var daysArray = BitConverter.GetBytes(days.Days);
var msecsArray = BitConverter.GetBytes((long)(msecs.TotalMilliseconds / 3.333333));
// Reverse the bytes to match SQL Servers ordering
Array.Reverse(daysArray);
Array.Reverse(msecsArray);
// Copy the bytes into the guid
Array.Copy(daysArray, daysArray.Length - 2, guidArray, guidArray.Length - 6, 2);
Array.Copy(msecsArray, msecsArray.Length - 4, guidArray, guidArray.Length - 4, 4);
return new Guid(guidArray);
}