how to subtract previous date from current date using c#

Question

i want to subtract previous date from current date. previous date may be 2 months and 15 days or 1 year 9 month and 10 days... like this etc... So please how can i write the Coding in C#. thanks a lot.

Answer 1

Any answer using TimeSpan will not be able to give you "2 months and 15 days" - as the length of a month changes over time.

Doing this using the base class libraries is a pain... which is one of the reasons I started the Noda Time project. Amongst its other features, it allows you to determine the Period between to dates (or dates and times, etc).

For example, let's see how long I've been on Stack Overflow:

LocalDate today = new LocalDate(2013, 2, 8);
LocalDate start = new LocalDate(2008, 9, 26);
// This defaults to using year, month, day units. You can specify alternatives.
Period period = Period.Between(start, today);

Console.WriteLine("{0} years; {1} months; {2} days",
                  period.Years, period.Months, period.Days);

Output:

4 years; 4 months; 13 days

Or if you actually wanted to subtract a period from a date (the question isn't very clear) you can do that too:

Period period = new PeriodBuilder { Years = 4, Months = 4, Days = 13 }.Build();
LocalDate today = new LocalDate(2013, 2, 8);
LocalDate start = today - period;
Console.WriteLine(start);

Output:

25 September 2008

Note that this doesn't give September 26th, because of the somewhat crazy nature of date/time arithmetic. If you added the period to September 26th you'd get today... but that's not the same thing. Treat this as a warning that you need to be really careful about describing what you want to achieve :)

This second side you can do with the BCL fairly easily though:

DateTime today = new DateTime(2013, 2, 8);
DateTime start = today.PlusYears(-4).PlusMonths(-4).PlusDays(-13);

There's no BCL type to represent that "years, months, days" value though.

Answer 2

Your question is a little confusing. Do you want to subtract one date from another date, or do you want to subtract a period of time from a date.

1. Subtract one date from another date:

DateTime previousDate = new DateTime(1990, 12, 12);
DateTime currentDate = DateTime.UtcNow;
TimeSpan difference = currentDate - previousDate;

You can then use the TimeSpan methods to get the difference in various units of time as you like.

Here's more info on TimeSpan: http://msdn.microsoft.com/en-us/library/system.timespan.aspx

2. Subtract a period of time from a date

DateTime currentDate = DateTime.UtcNow;
TimeSpan periodOfTime = new TimeSpan(12, 12, 0, 0);
DateTime newDate = currentDate - periodOfTime;

However, you'll have to calculate yourself what the length of a month is, if that's what you want.

Answer 3

You can use DateTime.Subtract.

Examples from article:

System.DateTime date1 = new System.DateTime(1996, 6, 3, 22, 15, 0);
System.DateTime date2 = new System.DateTime(1996, 12, 6, 13, 2, 0);
System.DateTime date3 = new System.DateTime(1996, 10, 12, 8, 42, 0);

// diff1 gets 185 days, 14 hours, and 47 minutes.
System.TimeSpan diff1 = date2.Subtract(date1);

// date4 gets 4/9/1996 5:55:00 PM.
System.DateTime date4 = date3.Subtract(diff1);

// diff2 gets 55 days 4 hours and 20 minutes.
System.TimeSpan diff2 = date2 - date3;

// date5 gets 4/9/1996 5:55:00 PM.
System.DateTime date5 = date1 - diff2;

Answer 4

TimeSpan timeSpan = new TimeSpan(2,2,0);
DateTime dateTime = DateTime.Now.Subtract(timeSpan);

Answer 5

When you subtract two date in C# you get a TimeSpan object. You can acces different properties of it to get the actual days, hours, minutes etc. taht it represents:

DateTime a;
DateTime b;

//assign some values

TimeSpan span = a.Subtract(b);
Console.WriteLine("Days: " + span.Days);

Answer 6

The following should do.

TimeSpan diff = DateTime.Now - previousDate;