System.DateTime Class | Compitionpoint C# Tutorials

The System.DateTime class of the .NET Framework allows you to use, store, and manipulate data of time and date. It has methods for manipulation of dates such as adding or subtracting days, months, or years to the current date and then returning the resulting date. It has some methods to show your date in various formats. The following code demonstrates how you can use the C# DateTime class to use time and date in your program.

using System;
 
public class Program
{
    public static void Main()
    {
        DateTime newyear = new DateTime(2010, 12, 25);
 
        Console.WriteLine(newyear.ToString());
    }
}

12/25/2010 12:00:00 AM

We used the constructor which accepts the year, the month, and the date to initialize our C# DateTime object. We used the ToString ()method of the C# DateTime class to display the date and time. The default ToString() method displays your C# DateTime object in this format: MM/DD/YYYY HH:MM:SS AM/PM. You will see that you have different methods to modify the formatting of the output. The C# DateTime method has multiple constructors that you can use. The table below lists some of the most basic ones.

Constructors
DateTime()
DateTime(int year, int month, int day)
DateTime(int year, int month, int day, int hour, int minute, int second)
DateTime(int year, int month, int day, int hour, int minute, int second, int millisecond)

Using the default parameterless constructor initializes the date to 01/01/0001 12:00:00 AM. To obtain the current date and time, you can use the Now static property of the C# DateTime class. To just get the current date, you can use the Today property.

DateTime now = DateTime.Now;
DateTime today = DateTime.Today;

To modify how your C# DateTime object will be presented, you can use several formatting methods available.

Method	Sample Output
ToLongDateString()	Saturday, Octoboer 2, 2010
ToLongTimeString()	4:14:18 PM
ToShortDateString()	10/2/2010
ToShortTimeString()	4:14 PM

You can even use the String.Format method to have a customized formatting.

Specifier	Type	Example	Output
dd	Day	{0:dd}	10
ddd	Day name	{0:ddd}	Tue
dddd	Full Day Name	{0:ddd}	Tuesday
f, ff, …	Second Fractions	{0:fff}	932
gg, …	Era	{0:gg}	A.D.
hh	2 digit hour	{0:hh}	10
HH	2 digit hour, 24hr format	{0:HH}	22
mm	Minute 00-59	{0:mm}	38
MM	Month 01-12	{0:MM}	12
MMM	Month abbreviation	{0:MMM}	Dec
MMMM	Full month name	{0:MMMM}	December
ss	Seconds 00-59	{0:ss}	46
tt	AM or PM	{0:tt}	PM
yy	Year, 2 digits	{0:yy}	02
yyyy	Year	{0:yyyy}	2002
zz	Timezone offset, 2 digits	{0:zz}	-05
zzz	Full timezone offset	{0:zzz}	-05:00
:	Seperator	{0:hh:mm:ss}	10:43:20
/	Seperator	{0:dd/MM/yyyy}	10/2/2010

For example:

Console.WriteLine("The current date is {0:dd/MM/yyy}", DateTime.Now);

The current date is 10/2/2010

C# DateTime Methods

The C# DateTime class provides some methods that deal with date and time data. Some of these methods are listed in the table below.

Method	Description
AddDays	Adds an amount of time to the value of the DateTime object. Accepts a double argument which indicates the amount of time to add. Use negative value to subtract time instead.
AddHours
AddMilliseconds
AddMinutes
AddMonths
AddSeconds
AddTicks
AddYears
Equals	Checks whether that DateTime object is equal to the DateTime argument passed to the method.
IsDaylightSavingTime	Check whether the instance of the DateTime is within the Daylight Saving Time range for the current time zone.
ToUniversalTime	Converts the value of the DateTime instance to Coordinated Universal Time (UTC)
DaysInMonth	Static. Returns the number of days of the specified month and year.
IsLeapYear	Static. Tells whether the specified year is a leap year.

Some of the properties of the DateTime class is listed below.

Property	Description
Date	Returns the date component.
Day	Returns the day of the month.
DayOfWeek	Returns the day of the week.
DayOfYear	Returns the day of the year.
Hour	Returns the hour component.
Millisecond	Returns the milliseconds component.
Minute	Returns the minute component.
Month	Returns the month component.
Second	Returns the second component.
TimeOfDay	Returns the current time of the day.
Year	Returns the year component.
Now	Static. Returns the current date and time.
Today	Static. Returns the current date only.
UtcNow	Static. Returns the current date and time in UTC.

Let’s take a look at another example that demonstrate the use of certain methods and properties of the DateTime class.

using System;
 
public class Program
{
    public static void Main()
    {
        DateTime myDate = DateTime.Now;
 
        Console.WriteLine("Year: " + myDate.Year);
        Console.WriteLine("Month: " + myDate.Month);
        Console.WriteLine("Day: " + myDate.Day);
        Console.WriteLine("Today is {0}.", myDate.DayOfWeek.ToString());
     
        //Assign newDate with the current date added by 3 days
        DateTime newDate = myDate.AddDays(3);
        Console.WriteLine("The date 3 days from now is {0}.", 
                  newDate.ToShortDateString());
 
        //Assign newdate with the current date subtracted by 3 days
        newDate = myDate.AddDays(-3);
        Console.WriteLine("The date 3 days ago is {0}.", newDate.ToShortDateString()); 
    }
}

Year: 2010
Month: 10
Day: 3
Today is Sunday.
The date 3 days from now is 10/6/2010.
The date 3 days ago is 9/30/2010.

We used the properties of the C# DateTime class to display the separate components of the date. We then demonstrate how we can modify a date by adding and subtracting days to the value of our C# DateTime object. Notice that we used a negative number when we subtracted 3 days. We also used the ToShortDateString() method to display a short form of the date.