How to display difference between two dates as 00Y 00M

Given two DateTimes in C#, how can I display the difference in years and months?

I can do basic arithmatic on the timespan that comes from a simple subtraction but this won't take into account the differing lengths of months, leap years etc.

Thanks for any help.

From stackoverflow

• You could try this:

  DateTime date1 = new DateTime(1954, 7, 30);
  DateTime today = DateTime.Now;
  
  TimeSpan span = today - date1;
  DateTime age = DateTime.MinValue + span;
  
  int years = age.Year - 1;
  int months = age.Month - 1;
  int days = age.Day - 1;
  
  Console.WriteLine("years: {0}, months: {1}, days: {2}", years, months, days);
  

  Stefan Steinegger : I think starting from MinValue is not correct. You get a value, but it has nothing to do with the current month. Of course, the difference is small, its about having a month of 28 instead of 31 days. But then you can also take the ticks and divide the year into 12 parts of the same size...

• Because the underlying representation is measured in 100-nanosecond ticks since 12:00 midnight, January 1, 1 A.D., a subtraction will handle leap years etc. quite correctly:

  DateTime date1 = ...
  DateTime date2 = ...
  
  // date2 must be after date1
  
  TimeSpan difference = date2.Subtract(date1);
  DateTime age=new DateTime(tsAge.Ticks); 
  
  int years = age.Years - 1;
  int months = age.Month - 1;
  
  Console.WriteLine("{0}Y, {1}M", years, months);
  

• Different length of month? Which month should it take? the time span is not bound to a certain year or month in the year. You can only count the days between two dates:

  Timspan span = date2 - date1;
  
  Console.Writeline("Days between date1 and date2: {0}", span.Days);
  

  Counting from DateTime.MinValue just take the year 0001 as start and counts the months from January. I don't think that this is of practical use.

  EDIT:

  Had another idea. You can count the month since date1:

  // primitive, inelegant, but should work if date1 < date2
  int years = date2.Year - date1.Year;
  int month = date2.Month - date1.Month;
  if (month < 0) 
  {
    years -= 1;
    month += 12;
  }
  Console.Writeline("{0}Y {1}M", years, month);
  

  The problem here is that you just ignore the days. After all it's not a good solution.

• FWIW here's what i've ended up with

          DateTime servicelength = new DateTime(DateTime.Now.Subtract(employee.StartDate).Ticks);
          LengthOfService.Text = String.Format("{0}Y {1}M", servicelength.Year - 1, servicelength.Month - 1);