DateTime difference in days on the basis of Date only

Question

I need to find the difference in days between two dates.

For example:

Input: **startDate** = 12-31-2012 23hr:59mn:00sec, **endDate** = 01-01-2013 00hr:

Answer 1

If you use the DateTime.Date property this will eliminate the time

date1.Date.Subtract(date2.Date).Days

Answer 2

Well, it sounds like you want the difference in the number of days, ignoring the time component. A DateTime with the time component reset to 00:00:00 is what the Date property gives you:

(startDate.Date - endDate.Date).TotalDays

Answer 3

Use TimeStamp. Just subtract two dates (using DateTime.Date property), get the difference in time span and return TotalDays

TimeSpan ts = endDate.Date - startDate.Date;
double TotalDays = ts.TotalDays;

So your extension method can be as simple as:

public static int GetDifferenceInDaysX(this DateTime startDate, DateTime endDate)
    {
      return (int) (endDate.Date - startDate.Date).TotalDays;
      // to return just a int part of the Total days, you may round it according to your requirement
    }

EDIT: Since the question has been edited, you may check the following example. Consider the following two dates.

DateTime startDate = new DateTime(2012, 12, 31, 23, 59, 00);
DateTime endDate = new DateTime(2013, 01, 01, 00, 15, 00); 

You can write the extension method as:

public static int GetDifferenceInDaysX(this DateTime startDate, DateTime endDate)
    {
        TimeSpan ts = endDate - startDate;
        int totalDays = (int) Math.Ceiling(ts.TotalDays);
        if (ts.TotalDays < 1 && ts.TotalDays > 0)
            totalDays = 1;
        else
            totalDays = (int) (ts.TotalDays);
        return totalDays;
    }

For the above dates it will give you 1