What is the easiest way to subtract time in C#?

I'm trying to put together a tool that will help me make work schedules. What is the easiest way to solve the following?

• 8:00am + 5 hours = 1:00pm
• 5:00pm - 2 hours = 3:00pm
• 5:30pm - :45 = 4:45

and so on.

Solution 1:

These can all be done with DateTime.Add(TimeSpan) since it supports positive and negative timespans.

DateTime original = new DateTime(year, month, day, 8, 0, 0);
DateTime updated = original.Add(new TimeSpan(5,0,0));

DateTime original = new DateTime(year, month, day, 17, 0, 0);
DateTime updated = original.Add(new TimeSpan(-2,0,0));

DateTime original = new DateTime(year, month, day, 17, 30, 0);
DateTime updated = original.Add(new TimeSpan(0,-45,0));

Or you can also use the DateTime.Subtract(TimeSpan) method analogously.

Solution 2:

Check out all the DateTime methods here: http://msdn.microsoft.com/en-us/library/system.datetime.aspx

Add Returns a new DateTime that adds the value of the specified TimeSpan to the value of this instance.

AddDays Returns a new DateTime that adds the specified number of days to the value of this instance.

AddHours Returns a new DateTime that adds the specified number of hours to the value of this instance.

AddMilliseconds Returns a new DateTime that adds the specified number of milliseconds to the value of this instance.

AddMinutes Returns a new DateTime that adds the specified number of minutes to the value of this instance.

AddMonths Returns a new DateTime that adds the specified number of months to the value of this instance.

AddSeconds Returns a new DateTime that adds the specified number of seconds to the value of this instance.

AddTicks Returns a new DateTime that adds the specified number of ticks to the value of this instance.

AddYears Returns a new DateTime that adds the specified number of years to the value of this instance.