System.DateTime Structure

The System.DateTime structure represents an instant in time, typically expressed as a date and time of day.

Syntax

public struct DateTime
{
    // Fields
    private long _dateData;

    // Constructors
    public DateTime(long ticks);
    public DateTime(int year, int month, int day);
    public DateTime(int year, int month, int day,
                    int hour, int minute, int second);
    public DateTime(int year, int month, int day,
                    int hour, int minute, int second,
                    DateTimeKind kind);
    // ... (other members omitted for brevity)
}

Constructors

Signature	Description
`DateTime(long ticks)`	Initializes a new instance using the specified number of ticks.
`DateTime(int year, int month, int day)`	Initializes a new instance to the specified year, month, and day. The time is set to 00:00:00.
`DateTime(int year, int month, int day, int hour, int minute, int second)`	Initializes a new instance to the specified date and time.
`DateTime(int year, int month, int day, int hour, int minute, int second, DateTimeKind kind)`	Initializes a new instance to the specified date, time, and kind.

Properties

Name	Type	Description
`Now`	`DateTime`	Gets the current date and time on this computer, expressed as the local time.
`UtcNow`	`DateTime`	Gets the current date and time expressed as the Coordinated Universal Time (UTC).
`Date`	`DateTime`	Gets the date component of this instance with the time component set to midnight.
`Day`	`int`	Gets the day of the month represented by this instance.
`Month`	`int`	Gets the month component of the date represented by this instance.
`Year`	`int`	Gets the year component of the date represented by this instance.
`Hour`	`int`	Gets the hour component of the time represented by this instance.
`Minute`	`int`	Gets the minute component of the time represented by this instance.
`Second`	`int`	Gets the second component of the time represented by this instance.
`Kind`	`DateTimeKind`	Gets a value indicating whether the time represented is local time, UTC, or neither.

Methods

Signature	Description
`Add(TimeSpan value)`	Returns a new DateTime that adds the specified time interval to the value of this instance.
`AddDays(double value)`	Returns a new DateTime that adds the specified number of days to the value of this instance.
`AddHours(double value)`	Returns a new DateTime that adds the specified number of hours to the value of this instance.
`Subtract(TimeSpan value)`	Returns a new DateTime that subtracts the specified time interval from the value of this instance.
`ToString(string format)`	Converts the value of the current DateTime object to its equivalent string representation using the specified format.
`ToUniversalTime()`	Converts the value of the current DateTime object to Coordinated Universal Time (UTC).
`ToLocalTime()`	Converts the value of the current DateTime object to local time.
`Parse(string s)`	Converts the specified string representation of a date and time to its DateTime equivalent.
`TryParse(string s, out DateTime result)`	Tries to convert a string representation of a date and time to its DateTime equivalent and returns a boolean indicating success.

Fields

Name	Type	Description
`MinValue`	`DateTime`	The smallest possible value of DateTime. Represents 00:00:00.0000000 UTC, January 1, 0001.
`MaxValue`	`DateTime`	The largest possible value of DateTime. Represents 23:59:59.9999999 UTC, December 31, 9999.

Operators

Operator	Description
`+`	Adds a TimeSpan to a DateTime, producing a new DateTime.
`-`	Subtracts a TimeSpan from a DateTime, or returns the TimeSpan between two DateTimes.
`==`	Determines whether two DateTime values are equal.
`!=`	Determines whether two DateTime values are not equal.
`<`	Determines whether one DateTime is earlier than another.
`>`	Determines whether one DateTime is later than another.

Examples

Display the current date and time in various formats:

using System;

class Program
{
    static void Main()
    {
        DateTime now = DateTime.Now;
        Console.WriteLine($"Default: {now}");
        Console.WriteLine($"ISO 8601: {now:yyyy-MM-ddTHH:mm:ss.fffK}");
        Console.WriteLine($"Long Date: {now:D}");
        Console.WriteLine($"Short Time: {now:t}");
    }
}

Calculate the number of days between two dates:

using System;

class AgeCalculator
{
    static void Main()
    {
        DateTime birthday = new DateTime(1990, 5, 15);
        DateTime today = DateTime.Today;
        TimeSpan age = today - birthday;
        Console.WriteLine($""You've lived {age.Days} days."");
    }
}