How do you calculate accumulative time in C#?

Question

I want to calculate the time span between 2 times which I saved in a database. So literally I want to know the length of time between the 2 values.

14:10:20 - 10:05:15 = 02:05:05

So the result would be 02:05:05.

How would I be able to achieve this using C#?

14:10:20 is the format I saved it in in my database.

Answer 1

Read the two time values into TimeSpan variables, then perform a .Subtract() on the bigger TimeSpan variable to get the TimeSpan result.

E.g. TimeSpan difference = t1.Subtract(t2);.

Answer 2

You will need to use the System.Diagnostics namespace:

    Stopwatch st=new Stopwatch() ;
    st.Start();

    // ...run what you want timed...

    st.Stop();

    Console.WriteLine("Elapsed = {0}", st.Elapsed.ToString());

Edit: apologies, just read the question properly!

Answer 3

DateTime objects support the "-" operator so you can just read your times into such objects and subtract them. To test, check this out:

DateTime then = DateTime.Now;
Thread.Sleep(500);
DateTime now = DateTime.Now;
TimeSpan time = now - then;
MessageBox.Show(time.ToString());

Answer 4

If you had stored your dates as datetime (and not string) then you could have done something like this:

CREATE TABLE testDate
(
    d1 datetime,
    d2 datetime
)
GO

create  function DateOnly(@DateTime DateTime)
-- Removes the time portion of a DateTime value.
returns datetime
as
    begin
    return dateadd(dd,0, datediff(dd,0,@DateTime))
    end
go
GO


INSERT INTO testDate (d1, d2) 
VALUES ('2008/09/22 09:12:58', '2008/09/22 11:15:09')
INSERT INTO testDate (d1, d2) 
VALUES ('2008/09/22 12:56:18', '2008/09/22 15:52:34')

----

select  (d2 - d1) - dbo.DateOnly(d2 - d1)  from testdate

If you have stored as strings then you will need to use DATEPART() to pull apart each of the indvidual time components.

Answer 5

Your first step will be to get the timevalues stored in your database into .NET DateTime structs.

If you stored them as SQL-DateTime values in the database you can get them directly as DateTime. It would look something like this:

SQLCommand getTimeCommand = new SQLCommand("SELECT time FROM table", dbConnection);
SQLDataReader myReader = getTimeCommand.ExecuteReader();
while (myReader.Read())
{
    DateTime time = myReader.GetDateTime(0);
}
myReader.Close();

Your implementation might differ, refer to the ADO.NET documentation in the MSDN library.

If you already got a string representing the time you can parse the string into a DateTime using the static methods

DateTime.Parse 

or

DateTime.ParseExact

In your case you might need to use ParseExact, which can pe provided with a format-string defining how to read the string. Examples should be found in the MSDN library.

Durations in .NET are stored inside a TimeSpan struct. Getting the elapsed time between to datetimes is easy:

DateTime time1, time2; //filled with your timevalues from the db
TimeSpan elapsed = d2 - d1;

elapsed now contains the timespan between the two DateTimes. There are several members for the struct to access the TimeSpan. Look into the MSDN-Library to find the ones you need.