using System;

public class Program

{

    public static void Main()

    {

        AuditLog auditLog = new AuditLog() {Created = new DateTime(2022,12,1,13,1,0)};

        auditLog.Created = auditLog.Created.Value.AddMilliseconds(567);

        auditLog.Created = auditLog.Created.Value.AddMicroseconds(123);

        var milliseconds1 = auditLog.Created.Value.GetMilliseconds();

        var milliseconds2 = auditLog.Created.Value.GetMilliseconds7();

        Console.WriteLine($"  Precision {auditLog.Created,-22}{milliseconds1}");

        Console.WriteLine($"Precision 7 {auditLog.Created,-22}{milliseconds2}");

        Console.WriteLine($" Mimic SSMS {auditLog.Created.Value:MM/dd/yyyy hh:mm:ss.fffffff}");

    }

}

public partial class AuditLog

{

    public int Id { get; set; }

​

    public string User { get; set; }

​

    public DateTime? Created { get; set; }

}

​

public static class Extensions

{

    public static int GetMilliseconds(this DateTime sender) 

        => Convert.ToInt32(sender.TimeOfDay.Milliseconds.ToString() + sender.TimeOfDay.Microseconds.ToString());

    public static int GetMilliseconds7(this DateTime sender) 

        => Convert.ToInt32((sender.TimeOfDay.Milliseconds.ToString() + sender.TimeOfDay.Microseconds.ToString())

            .PadRight(7, '0')); 

}