CODEWITHSUNDEEP
c#datedate-comparison
csharpMind
csharpMind

Reputation: 89

c#: How do I get the previous year-to-date and previous month-to-date for specific time periods?

Using c#, I want to compare the current week-to-date to the same period last week-to-date. For example, if today is Wednesday, and if the first day of the week is Sunday, then I want to compare totals for Sunday – Tuesday of this week against Sunday – Tuesday of last week. I’m not counting Wednesday because I don’t have a full day of data until midnight the same day.

The same applies to comparing this mtd to the same number of days last month, and last year. For example, if the current date is June 19th, I want to compare the data from May 1-18th of last month as well as January 1 – June 18th of last year against January 1 – June 18th of this year.

The variables I’m trying to use look like this:

//Current dates
DateTime currentDte = DateTime.Now;
DateTime beginWeek = DateTime.Now.StartOfWeek(DayOfWeek.Sunday);
DateTime beginMonth = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1);
DateTime beginYear = new DateTime(DateTime.Now.Year, 1, 1);

//Historical dates
DateTime lastWeekToDate = DateTime.Now.StartOfWeek(DayOfWeek.Sunday - (7 - (int)DateTime.Now.DayOfWeek));
DateTime lastMonthToDate =
DateTime lastYearToDate =

As you can see I figured out the current dates and can loop through them to get the wtd, mtd, and ytd data I need. And I managed to figure out how to get the last week-to-date I need.

But I don’t know how to get the lastMonthToDate and lastYearToDate dates I need. I’ve tried everything I can think of. I’ve read date documentation until my eyes hurt, and still I come up with goose eggs. Can anyone offer any suggestions?

Upvotes: 0

Views: 3818

Answers (2)

csharpMind
csharpMind

Reputation: 89

Based on the feedback I received from Zeph, I was able to get the beginning of last year using this code:

DateTime startDate = beginYear.AddYears(-1);

Now I'm able to tally all of the ytd data I need based on the interval dates. Thank you very much!

Upvotes: 0

Zeph
Zeph

Reputation: 1728

If I understand your question correctly, you just need to use AddMonths and AddYears. 

DateTime lastMonthToDate = beginMonth.AddMonths(-1);
DateTime lastYearToDate  = beginYear.AddYears(-1);

EDIT

Based your comment - it looks like you want the to subtract months/years from the current date in which case it would be 

DateTime lastMonthToDate = currentDte.AddMonths(-1);
DateTime lastYearToDate  = currentDte.AddYears(-1);

If it's the time of day that's throwing you off, just use the date part DateTime.Now.Date.AddMonths(-1)

Upvotes: 1

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