Stephens' C# Programming with Visual Studio® 2010 24-Hour Trainer

Working with Dates and Times

One of C#’s more confusing data types is DateTime. A DateTime represents a date, a time, or

both. For example, a

DateTime variable might represent Thursday April 1, 2010 at 9:15 AM.

In this lesson, you learn how to work with dates and times. You learn how to create

DateTime

variables, find the current date and time, and calculate elapsed time.

CREATING DATETIME VARIABLES

C# doesn’t have DateTime literal values so you cannot simply set a DateTime variable equal

to a value as you can with some other data types. Instead you can use the

new keyword to

initialize a new

DateTime variable, supplying arguments to define the date and time.

For example, the following code creates a

DateTime variable named aprilFools and initializes

it to the date April 1, 2010. It then displays the date using the short date format described in

Lesson 14 and by calling the variable’s

ToShortDateString method.

DateTime aprilFools = new DateTime(2010, 4, 1);

MessageBox.Show(aprilFools.ToString(“d”));

MessageBox.Show(aprilFools.ToShortDateString());

The preceding code uses a year, month, and day to initialize its DateTime variable, but the

DateTime type lets you use many different kinds of values. The three most useful combinations

of arguments specify (all as integers):

Year, month, day

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Year, month, day, hour, minute, second

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Year, month, day, hour, minute, second, milliseconds

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