using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine($"Type: {TimeInterval.MilliSecond.ToDateTimeInterval().GetType()} | Value: {TimeInterval.MilliSecond.ToDateTimeInterval()}");

        Console.WriteLine($"Type: {DateInterval.Month.ToDateTimeInterval().GetType()} | Value: {DateInterval.Month.ToDateTimeInterval()}");

    }

}

​

public enum DateInterval { Off, Day, Month, Year };

public enum TimeInterval { Off, MilliSecond, Second, Minute, Hour };

public enum DateTimeInterval { Off, MilliSecond, Second, Minute, Hour, Day, Month, Year };

​

public static class DateIntervalHelper 

{

    public static DateTimeInterval ToDateTimeInterval(this TimeInterval aInterval)

    {

        if (Enum.TryParse<DateTimeInterval>(aInterval.ToString(), out var @enum))

            return @enum;

​

        return DateTimeInterval.Off;

    }

    public static DateTimeInterval ToDateTimeInterval(this DateInterval aInterval)

    {

        if (Enum.TryParse<DateTimeInterval>(aInterval.ToString(), out var @enum))

            return @enum;

​

        return DateTimeInterval.Off;

    }

}