App Date Helper (Date Ranges)

using System;

namespace AH
{
      /// <summary>
      /// The AppDateHelper class provides routines to make it easy to work with dates.
      /// </summary>
      ///
      [System.Diagnostics.DebuggerStepThrough()]
      public class AppDateHelper
      {
            /// <summary>
            /// Defines a list of date ranges, useful for creating a start and end date on reports.
            /// </summary>
            private static string[] iDateRangeNames =
                  {
                        /* 0  */ "All",
                        /* 1  */ "Today",
                        /* 2  */ "This Week",
                        /* 3  */ "This Week-to-date",
                        /* 4  */ "This Month",
                        /* 5  */ "This Month-to-date",
                        /* 6  */ "This Quarter",
                        /* 7  */ "This Quarter-to-date",
                        /* 8  */ "This Year",
                        /* 9  */ "This Year-to-date",
                        /* 10 */ "Yesterday",
                        /* 11 */ "Last Week",
                        /* 12 */ "Last Month",
                        /* 13 */ "Last Quarter",
                        /* 14 */ "Last Year"
                        /* 15 */
                  };
            public static bool GetDates(string dateRangeName, out DateTime startDate, out DateTime stopDate)
            {
                  return GetDates(dateRangeName,DateTime.Today,out startDate,out stopDate);
            }
            /// <summary>
            /// Based on iDateRangeName, returns 2 dates the are set to the correct start and stop dates.
            /// </summary>
            /// <param name="dateRangeName">
            /// Specifies the date range to set to the dates for. Must be one of the DateRangeNames elements.
            /// </param>
            /// <param name="startDate">
            /// On function return, set to the starting date based on dateRangeName.
            /// </param>
            /// <param name="stopDate">
            /// On function return, set to the stopping date based on dateRangeName.
            /// </param>
            public static bool GetDates(string dateRangeName,DateTime todayDate, out DateTime startDate, out DateTime stopDate)
            {
                  DateTime StartDate = todayDate;
                  DateTime StopDate = todayDate;
                  bool result = true;

                  // All.
                  if (dateRangeName == DateRangeNames[0])
                  {
                        StartDate = new DateTime(1900, 1, 1);
                        StopDate = new DateTime(2100, 12, 31);
                  }

                  // Today.
                  if (dateRangeName == DateRangeNames[1])
                  {
                        StartDate = DateTime.Today;
                        StopDate = DateTime.Today;
                  }

                  // This Week.
                  if (dateRangeName == DateRangeNames[2])
                  {
                        // Set StartDate to most recent Sunday, first day of the current week.
                        DateTime Dt = DateTime.Today;
                        while (Dt.DayOfWeek != DayOfWeek.Sunday)
                              Dt = Dt.AddDays(-1);
                        StartDate = Dt;

                        // Set StopDate to the last day of this week, which is Saturday.
                        Dt = DateTime.Today;
                        while (Dt.DayOfWeek != DayOfWeek.Saturday)
                              Dt = Dt.AddDays(1);
                        StopDate = Dt;
                  }

                  // This Week-to-date.
                  if (dateRangeName == DateRangeNames[3])
                  {
                        // Set StartDate to most recent Sunday, first day of the current week.
                        DateTime Dt = DateTime.Today;
                        while (Dt.DayOfWeek != DayOfWeek.Sunday)
                              Dt = Dt.AddDays(-1);
                        StartDate = Dt;

                        // Set StopDate to today.
                        StopDate = DateTime.Today;
                  }

                  // This Month.
                  if (dateRangeName == DateRangeNames[4])
                  {
                        // Set StartDate to first of current month.
                        StartDate = new DateTime(DateTime.Today.Year, DateTime.Today.Month, 1);

                        // Set StopDate to last date of current month.
                        DateTime Dt = new DateTime(DateTime.Today.Year, DateTime.Today.AddMonths(1).Month, 1).AddDays(-1);
                        StopDate = new DateTime(DateTime.Today.Year, DateTime.Today.Month, Dt.Day);
                  }

                  // This Month-to-date.
                  if (dateRangeName == DateRangeNames[5])
                  {
                        // Set StartDate to first of current month.
                        StartDate = new DateTime(DateTime.Today.Year, DateTime.Today.Month, 1);

                        // Set StopDate to today.
                        StopDate = DateTime.Today;
                  }

                  // This Quarter.
                  if (dateRangeName == DateRangeNames[6])
                  {
                        // Set StartDate to first day of the 1st month of this quarter.
                        int CurrentMonth = DateTime.Today.Month;
                        DateTime Dt = DateTime.Today;
                        while ((CurrentMonth %3) != 0)
                        {
                              Dt = Dt.AddMonths(-1);
                              CurrentMonth--;
                        }
                        StartDate = new DateTime(Dt.Year, Dt.Month, 1);

                        // Set StopDate to last date of current month.
                        Dt = StartDate.AddMonths(4).AddDays(-1);
                        StopDate = Dt;
                  }

                  // This Quarter-to-date.
                  if (dateRangeName == DateRangeNames[7])
                  {
                        // Set StartDate to first day of the 1st month of this quarter.
                        int CurrentMonth = DateTime.Today.Month;
                        DateTime Dt = DateTime.Today;
                        while ((CurrentMonth %3) != 0)
                        {
                              Dt = Dt.AddMonths(-1);
                              CurrentMonth--;
                        }
                        StartDate = new DateTime(Dt.Year, Dt.Month, 1);

                        // Set StopDate to today.
                        StopDate = DateTime.Today;
                  }

                  // This Year.
                  if (dateRangeName == DateRangeNames[8])
                  {
                        // Set StartDate to first day of the year.
                        StartDate = new DateTime(DateTime.Today.Year, 1, 1);

                        // Set StopDate to last day of the year.
                        StopDate = new DateTime(StartDate.AddYears(1).Year, 1, 1).AddDays(-1);
                  }

                  // This Year-to-date.
                  if (dateRangeName == DateRangeNames[9])
                  {
                        // Set StartDate to first day of the year.
                        StartDate = new DateTime(DateTime.Today.Year, 1, 1);

                        // Set StopDate to today.
                        StopDate = DateTime.Today;
                  }

                  // Yesterday.
                  if (dateRangeName == DateRangeNames[10])
                  {
                        // Set StartDate to yesterday.
                        StartDate = DateTime.Today.AddDays(-1);

                        // Set StopDate to yesterday.
                        StopDate = DateTime.Today.AddDays(-1);
                  }

                  // Last Week.
                  if (dateRangeName == DateRangeNames[11])
                  {
                        // Set StartDate to the first day of last week.
                        StartDate = DateTime.Today.AddDays(-7);
                        while (StartDate.DayOfWeek != System.DayOfWeek.Sunday)
                              StartDate = StartDate.AddDays(-1);

                        // Set StopDate to the last day of last week, which was last Saturday.
                        // If the current day is Saturday, then go to the previous Saturday.
                        StopDate = DateTime.Today.AddDays(-1);
                        while (StopDate.DayOfWeek != System.DayOfWeek.Saturday)
                              StopDate = StopDate.AddDays(-1);
                  }

                  // Last Month.
                  if (dateRangeName == DateRangeNames[12])
                  {
                        // Set StartDate to the first day of last month.
                        StartDate = new DateTime(DateTime.Today.AddMonths(-1).Year, DateTime.Today.AddMonths(-1).Month, 1);

                        // Set StopDate to the last day of last month.
                        StopDate = new DateTime(DateTime.Today.Year, DateTime.Today.Month, 1).AddDays(-1);
                  }

                  // Last Quarter.
                  if (dateRangeName == DateRangeNames[13])
                  {
                        // Set StartDate to the first day of the first month of the previous quarter.
                        int CurrentMonth = DateTime.Today.Month;
                        DateTime Dt = DateTime.Today;
                        while ((CurrentMonth %3) != 0)
                        {
                              Dt = Dt.AddMonths(-1);
                              CurrentMonth--;
                        }
                        StartDate = Dt.AddMonths(-3);

                        // Set StopDate to the last day of last month.
                        StopDate = StartDate.AddMonths(4).AddDays(-1);
                  }

                  // Last Year.
                  if (dateRangeName == DateRangeNames[14])
                  {
                        // Set StartDate to first day of the last year.
                        StartDate = new DateTime(DateTime.Today.AddYears(-1).Year, 1, 1);

                        // Set StopDate to the last day of the last year.
                        StopDate = StartDate.AddYears(1).AddDays(-1);
                  }

            //// Custom.
            //if (dateRangeName == DateRangeNames[15])
            //{
            //    // Don't return anything.
            //    result = false;
            //}

                  startDate = StartDate;
                  stopDate = StopDate;

                  return result;
            }

            /// <summary>
            /// Defines a list of date ranges, useful for creating a start and end date on reports.
            /// </summary>
            public static string[] DateRangeNames
            {
                  get { return iDateRangeNames; }
            }

            /// <summary>
            /// Returns a starting date based on today's date, for the dateRangeName.
            /// </summary>
            public static DateTime GetStartDate(string dateRangeName)
            {
                  DateTime StartDate;
                  DateTime StopDate;
                  GetDates(dateRangeName, out StartDate, out StopDate);

                  return StartDate;
            }

            /// <summary>
            /// Returns a stopping date based on today's date, for the dateRangeName.
            /// </summary>
            public static DateTime GetStopDate(string dateRangeName)
            {
                  DateTime StartDate;
                  DateTime StopDate;
                  GetDates(dateRangeName, out StartDate, out StopDate);

                  return StopDate;
            }
      }
}