Here, I have described how to get dates between two dates with an interval of days, such the dates of the last 4 weeks, and how to get the start date and end date with a range.
By this method, you can get dates between two dates with an interval of days or you can use months also. In this method, we have to pass three parameters.
  • startDate :
  • endDate
  • intVal
  1. public static void getDateRange(string startDate, string endDate, int intVal)
  2. {
  3. for (DateTime date = DateTime.Parse(startDate); date <= DateTime.Parse(endDate); date = date.AddDays(intVal))
  4. {
  5. Console.WriteLine(date.ToString("yyyy-MM-dd"));
  6. }
  7. }
In the above method, we will get the dates with an interval of 2 days. Now, call the getDateRange.
  1. public static void Main()
  2. {
  3. getDateRange("2019-01-01", "2019-01-30", 2);
  4. }

Get The Date Range of the Last 4 Weeks

In this method, we have to pass one parameter, i.e., year, and get the last four-week start date and end date.
  1. public static void getLast4WeekRanges(int year)
  2. {
  3. int dd = int.Parse(DateTime.Now.ToString("dd"));
  4. int mm = int.Parse(DateTime.Now.ToString("MM"));
  5. string currentDayinYear = new DateTime(year, mm, dd).ToString("yyyy-MM-dd");
  6. DayOfWeek dDay = DateTime.Now.DayOfWeek;
  7. int days = dDay - DayOfWeek.Monday;
  8. string lastWeekDay;
  9. if (days == 0)
  10. {
  11. lastWeekDay = DateTime.Now.AddDays(-7).ToString("yyyy-MM-dd");
  12. }
  13. else
  14. {
  15. lastWeekDay = DateTime.Now.AddDays(-days).ToString("yyyy-MM-dd");
  16. }
  18. string lastWeekEndDay = DateTime.Parse(lastWeekDay).AddDays(6).ToString("yyyy-MM-dd");
  19. Console.WriteLine("startdate: {0}, enddate: {1}, currentweek: {2}", lastWeekDay, lastWeekEndDay, true);
  21. for (int i = 0; i < 3; i++)
  22. {
  23. lastWeekDay = DateTime.Parse(lastWeekDay).AddDays(-7).ToString("yyyy-MM-dd");
  24. lastWeekEndDay = DateTime.Parse(lastWeekDay).AddDays(6).ToString("yyyy-MM-dd");
  25. Console.WriteLine("startdate: {0}, enddate: {1}, currentweek: {2}", lastWeekDay, lastWeekEndDay, false);
  26. }
  27. }
Now, call the getLast4WeekRanges.
  1. public static void Main()
  2. {
  3. getLast4WeekRanges(2019);
  4. }

Get start date and end date with a day range

In this method, we will pass a day range like TODAY, LASTWEEK, LASTMONTH, etc and get the start and end date.
  1. public static void getStartEndDate(string dateRange)
  2. {
  3. string startDate, endDate;
  4. string currentDate = DateTime.Now.ToString("yyyy-MM-dd");
  5. switch (dateRange)
  6. {
  7. case "TODAY":
  8. startDate = currentDate;
  9. endDate = currentDate;
  10. break;
  11. case "LASTWEEK":
  12. DayOfWeek desiredDay = DayOfWeek.Monday;
  13. int offsetAmount = (int)desiredDay - (int)DateTime.Now.DayOfWeek;
  14. DateTime lastWeekDesiredDay = DateTime.Now.AddDays(-7 + offsetAmount);
  15. startDate = lastWeekDesiredDay.ToString("yyyy-MM-dd");
  16. endDate = DateTime.Parse(startDate).AddDays(6).ToString("yyyy-MM-dd");
  17. break;
  18. case "LASTMONTH":
  19. DateTime LastMonthLastDate = DateTime.Now.AddDays(0 - DateTime.Now.Day);
  20. DateTime LastMonthFirstDate = LastMonthLastDate.AddDays(1 - LastMonthLastDate.Day);
  21. startDate = LastMonthFirstDate.ToString("yyyy-MM-dd");
  22. endDate = LastMonthLastDate.ToString("yyyy-MM-dd");
  23. break;
  24. case "MONTHLY":
  25. startDate = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1).ToString("yyyy-MM-dd");
  26. endDate = currentDate;
  27. break;
  28. case "LASTTHREEMONTHS":
  29. DateTime LastMonthLastDate1 = DateTime.Now.AddDays(0 - DateTime.Now.Day);
  30. DateTime LastMonthFirstDate1 = LastMonthLastDate1.AddDays(1 - LastMonthLastDate1.Day);
  31. startDate = LastMonthFirstDate1.AddMonths(-2).ToString("yyyy-MM-dd");
  32. endDate = LastMonthLastDate1.ToString("yyyy-MM-dd");
  33. break;
  34. case "YEARLY":
  35. startDate = new DateTime(DateTime.Now.Year, 1, 1).ToString("yyyy-MM-dd");
  36. endDate = currentDate;
  37. break;
  38. default:
  39. startDate = currentDate;
  40. endDate = currentDate;
  41. break;
  42. }
  43. Console.WriteLine("startdate: {0}, enddate: {1}", startDate, endDate);
  44. }
Now, call the getStartEndDate.
  1. public static void Main()
  2. {
  3. getStartEndDate("TODAY");
  4. getStartEndDate("LASTWEEK");
  5. getStartEndDate("LASTMONTH");
  6. getStartEndDate("MONTHLY");
  7. getStartEndDate("LASTTHREEMONTHS");
  8. getStartEndDate("YEARLY");
  9. }