using System;

public class Program

{

    private static void Main()

    {

​

​

​

            public DateTime Start = new DateTime(now.Year, now.Month, 1).AddMonths(-2).Date;

            public DateTime End = now.Date;

        Console.WriteLine(Start);

        Console.WriteLine(End);     

    }

        public static DateSpan GenerateDateSpan(DateRange range)

        {

            var result = new DateSpan();

            var now = DateTime.Now;

            switch (range)

            {

                case DateRange.LastWeek:

                    result.Start = now.AddDays(-7).Date;

                    result.End = now.AddDays(-1).Date;

                    break;

                case DateRange.LastMonth:

                    result.Start = new DateTime(now.Year, now.Month, 1).Date;

                    result.End = new DateTime(now.Year, now.Month, DateTime.DaysInMonth(now.Year, now.Month));

                    break;

                case DateRange.ThreeMonths:

                    result.Start = new DateTime(now.Year, now.Month, 1).AddMonths(-2).Date;

                    result.End = now.Date;

                    break;

                case DateRange.SixMonths:

                    result.Start = new DateTime(now.Year, now.Month, 1).AddMonths(-5).Date;

                    result.End = now.Date;

                    break;

                default:

                    throw new ArgumentOutOfRangeException("range");

            }

​

            return result;

        }   

}