Csharp/C Sharp/Development Class/Date Time
Содержание
- 1 Add 2 month to the date time
- 2 Add TimeSpan to DateTime
- 3 A simple clock
- 4 comparisons between DateTime objects
- 5 Constructors of DateTime
- 6 Current date and time
- 7 DateTime and TimeSpan Instances
- 8 DateTime Now and its calculation
- 9 Displays the words "Hello World!" on the screen, along with the current date and time
- 10 display the Date, Day, DayOfWeek, DayOfYear,Ticks, and TimeOfDayProperties of myDateTime
- 11 Do some leap year checks
- 12 Estimates pi by throwing points into a square. Use to compare execution times
- 13 Illustrates the use of DateTime and TimeSpan instances
- 14 illustrates the use of TimeSpan properties and methods
- 15 Look at the min and max date/time values
- 16 Measures the time taken to add some numbers
- 17 new DateTime( 29)
- 18 new DateTime( 29, new JulianCalendar())
- 19 Offset of DateTime
- 20 Output DateTime object
- 21 Parse and ParseExact
- 22 Specify Kind DateTime
- 23 use the Add() method to add a TimeSpan to a DateTime
- 24 use the AddYears(), AddMonths(), AddDays(), AddMinutes(), and AddSeconds() methods to add periods to a DateTime
- 25 use the Compare() method to compare DateTime instances
- 26 use the DaysInMonth() method to retrieve the number of days in a particular month and year
- 27 use the Equals() method to compare DateTime instances
- 28 use the IsLeapYear() method to determine if a particular year is a leap year
- 29 use the Now and UtcNow properties to get the currrent date and time
- 30 use the overloaded addition operator (+) to add a TimeSpan to a DateTime
- 31 use the overloaded less than operator (
- 32 use the overloaded subtraction operator (-) to subtract a TimeSpan from a DateTime
- 33 use the Parse() method to convert strings to DateTime instances
- 34 use the Subtract() method to subtract a TimeSpan from a DateTime
- 35 What day of the month is this?
Add 2 month to the date time
<source lang="csharp"> using System; using System.Collections.Generic; using System.Text; class Program {
static void Main(string[] args) { DateTime dt = new DateTime(2004, 10, 17); dt.AddMonths(2); // Month is now December. Console.WriteLine("Daylight savings: {0}", dt.IsDaylightSavingTime()); }
}
</source>
Add TimeSpan to DateTime
<source lang="csharp"> using System; using System.Globalization; class MainClass {
public static void Main() { DateTime dt = new DateTime(); DateTime dt1 = new DateTime(2001, 12, 31); DateTime dt2 = new DateTime(2000, 12, 31, 23, 59, 59); TimeSpan year = new TimeSpan(365 * TimeSpan.TicksPerDay); for (int i = 0; i < 10; ++i) dt += year; Console.WriteLine("DT as string: {0}", dt.ToString()); }
}
</source>
A simple clock
<source lang="csharp"> /* C#: The Complete Reference by Herbert Schildt Publisher: Osborne/McGraw-Hill (March 8, 2002) ISBN: 0072134852
- /
// A simple clock.
using System;
public class SimpleClock {
public static void Main() { string t; int seconds; DateTime dt = DateTime.Now; seconds = dt.Second; for(;;) { dt = DateTime.Now; // update time if seconds change if(seconds != dt.Second) { seconds = dt.Second; t = dt.ToString("T"); if(dt.Minute==0 && dt.Second==0) t = t + "\a"; // ring bell at top of hour Console.WriteLine(t); } } }
}
</source>
comparisons between DateTime objects
<source lang="csharp"> using System; using System.Globalization; class MainClass {
public static void Main() { // Create some date/time objects DateTime dt = new DateTime(); DateTime dt1 = new DateTime(2001, 12, 31); DateTime dt2 = new DateTime(2000, 12, 31, 23, 59, 59); if (dt2 < dt1) Console.WriteLine("Dt2 < Dt1"); else if (dt2 == dt1) Console.WriteLine("Dt2 == Dt1"); else Console.WriteLine("Dt2 > Dt1"); }
}
</source>
Constructors of DateTime
<source lang="csharp"> using System; using System.Globalization; class MainClass {
public static void Main() { DateTime dt = new DateTime(); DateTime dt1 = new DateTime(2001, 12, 31); DateTime dt2 = new DateTime(2000, 12, 31, 23, 59, 59); // Print them out as strings Console.WriteLine("DT as string: {0}", dt.ToString()); Console.WriteLine("DT1 as string: {0}", dt1.ToString()); Console.WriteLine("DT2 as string: {0}", dt2.ToString()); }
}
</source>
Current date and time
<source lang="csharp"> using System; using System.Globalization; class MainClass {
public static void Main() { Console.WriteLine("Current Date and Time: {0}", DateTime.Now.ToString()); Console.WriteLine("Current Date Only: {0}", DateTime.Today.ToString()); }
}
</source>
DateTime and TimeSpan Instances
<source lang="csharp"> using System; class MainClass {
public static void DisplayDateTime(string name, DateTime myDateTime) { Console.WriteLine(name + " = " + myDateTime); Console.WriteLine(name + ".Year = " + myDateTime.Year); Console.WriteLine(name + ".Month = " + myDateTime.Month); Console.WriteLine(name + ".Day = " + myDateTime.Day); Console.WriteLine(name + ".Hour = " + myDateTime.Hour); Console.WriteLine(name + ".Minute = " + myDateTime.Minute); Console.WriteLine(name + ".Second = " + myDateTime.Second); Console.WriteLine(name + ".Millisecond = " + myDateTime.Millisecond); Console.WriteLine(name + ".Ticks = " + myDateTime.Ticks); } public static void Main() { int year = 2008; int month = 8; int day = 25; DateTime myDateTime = new DateTime(year, month, day); int hour = 23; int minute = 30; int second = 12; int millisecond = 5; DateTime myDateTime2 = new DateTime(year, month, day, hour, minute, second, millisecond); System.Globalization.JulianCalendar myCalendar = new System.Globalization.JulianCalendar(); DateTime myDateTime3 = new DateTime(year, month, day, myCalendar); DateTime myDateTime4 = new DateTime(0); DisplayDateTime("myDateTime", myDateTime); DisplayDateTime("myDateTime2", myDateTime2); DisplayDateTime("myDateTime3", myDateTime3); DisplayDateTime("myDateTime4", myDateTime4); TimeSpan myTimeSpan = new TimeSpan(4, 12, 10); myDateTime4 += myTimeSpan; DisplayDateTime("myDateTime4", myDateTime4); }
}
</source>
DateTime Now and its calculation
<source lang="csharp"> using System;
class MainClass { public static void Main() { TimeSpan timespan1 = new TimeSpan(2, 12, 0, 0); TimeSpan timespan2 = new TimeSpan(4, 12, 0, 0); TimeSpan oneWeek = timespan1 + timespan2; DateTime now = DateTime.Now; DateTime past = now - oneWeek; DateTime future = now + oneWeek; Console.WriteLine("Now : {0}", now); Console.WriteLine("Past : {0}", past); Console.WriteLine("Future: {0}", future); } } </source>
Displays the words "Hello World!" on the screen, along with the current date and time
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example1_1.cs: a variation on the classic "Hello World!" program. This program displays the words "Hello World!" on the screen, along with the current date and time
- /
public class Example1_1 {
public static void Main() { // display "Hello World!" on the screen System.Console.WriteLine("Hello World!"); // display the current date and time System.Console.WriteLine("The current date and time is " + System.DateTime.Now); }
}
</source>
display the Date, Day, DayOfWeek, DayOfYear,Ticks, and TimeOfDayProperties of myDateTime
<source lang="csharp"> using System; class MainClass {
public static void Main() { DateTime myDateTime = DateTime.Now; Console.WriteLine("myDateTime.Date = " + myDateTime.Date); Console.WriteLine("myDateTime.Day = " + myDateTime.Day); Console.WriteLine("myDateTime.DayOfWeek = " + myDateTime.DayOfWeek); Console.WriteLine("myDateTime.DayOfYear = " + myDateTime.DayOfYear); Console.WriteLine("myDateTime.Ticks = " + myDateTime.Ticks); Console.WriteLine("myDateTime.TimeOfDay = " + myDateTime.TimeOfDay); }
}
</source>
Do some leap year checks
<source lang="csharp"> using System; using System.Globalization; class MainClass {
public static void Main() { // int[] years = { 1984, 2000, 1999, 2002 }; for (int i = 0; i < years.Length; ++i) { if (DateTime.IsLeapYear(years[i])) Console.WriteLine("Year {0} is a leap year", years[i]); else Console.WriteLine("Year {0} is NOT a leap year", years[i]); } }
}
</source>
Estimates pi by throwing points into a square. Use to compare execution times
<source lang="csharp"> /* C# Programming Tips & Techniques by Charles Wright, Kris Jamsa Publisher: Osborne/McGraw-Hill (December 28, 2001) ISBN: 0072193794
- /
// // CalcPi.cs -- Estimates pi by throwing points into a square. Use to // compare execution times. // // Compile this program with the following command line: // C:>csc CalcPi.cs // namespace CalcPi {
using System; public class CalcPi { static void Main () { const int throws = 10000000; DateTime now = DateTime.Now; Random rand = new Random ((int) now.Millisecond); int Inside = 0; for (int i = 0; i < throws; ++i) { double cx = rand.NextDouble(); double cy = rand.NextDouble(); double distance = Math.Sqrt ((cx * cx) + (cy * cy)); if (distance < 1.0) ++Inside; } double pi = 4 * (double) Inside / (double) throws; DateTime End = DateTime.Now; TimeSpan Diff = End - now; Console.WriteLine ("pi = " + pi); Console.WriteLine ("Milliseconds = " + Diff.TotalMilliseconds); } }
}
</source>
Illustrates the use of DateTime and TimeSpan instances
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example9_3.cs illustrates the use of DateTime and TimeSpan instances
- /
using System; public class Example9_3 {
public static void DisplayDateTime( string name, DateTime myDateTime ) { Console.WriteLine(name + " = " + myDateTime); // display the DateTime"s properties Console.WriteLine(name + ".Year = " + myDateTime.Year); Console.WriteLine(name + ".Month = " + myDateTime.Month); Console.WriteLine(name + ".Day = " + myDateTime.Day); Console.WriteLine(name + ".Hour = " + myDateTime.Hour); Console.WriteLine(name + ".Minute = " + myDateTime.Minute); Console.WriteLine(name + ".Second = " + myDateTime.Second); Console.WriteLine(name + ".Millisecond = " + myDateTime.Millisecond); Console.WriteLine(name + ".Ticks = " + myDateTime.Ticks); }
public static void Main() { // create a DateTime instance, specifying the year, // month, and day int year = 2002; int month = 12; int day = 25; DateTime myDateTime = new DateTime(year, month, day); // create a DateTime instance, specifying the year, // month, day, hour, minute, second, and millisecond int hour = 23; int minute = 30; int second = 12; int millisecond = 5; DateTime myDateTime2 = new DateTime(year, month, day, hour, minute, second, millisecond); // create a DateTime instance, specifying the year, // month, day, and JulianCalendar object System.Globalization.JulianCalendar myCalendar = new System.Globalization.JulianCalendar(); DateTime myDateTime3 = new DateTime(year, month, day, myCalendar); // create a DateTime instance, specifying the number of ticks DateTime myDateTime4 = new DateTime(0); // display the various DateTime instances DisplayDateTime("myDateTime", myDateTime); DisplayDateTime("myDateTime2", myDateTime2); DisplayDateTime("myDateTime3", myDateTime3); DisplayDateTime("myDateTime4", myDateTime4); // create a TimeSpan instance, and add it to myDateTime4 TimeSpan myTimeSpan = new TimeSpan(4, 12, 10); myDateTime4 += myTimeSpan; DisplayDateTime("myDateTime4", myDateTime4); }
}
</source>
illustrates the use of TimeSpan properties and methods
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example9_5.cs illustrates the use of TimeSpan properties and methods
- /
using System; public class Example9_5 {
public static void DisplayTimeSpan( string name, TimeSpan myTimeSpan ) { Console.WriteLine(name + " = " + myTimeSpan); // display the TimeSpan"s properties Console.WriteLine(name + ".Days = " + myTimeSpan.Days); Console.WriteLine(name + ".Hours = " + myTimeSpan.Hours); Console.WriteLine(name + ".Minutes = " + myTimeSpan.Minutes); Console.WriteLine(name + ".Seconds = " + myTimeSpan.Seconds); Console.WriteLine(name + ".Milliseconds = " + myTimeSpan.Milliseconds); Console.WriteLine(name + ".Ticks = " + myTimeSpan.Ticks); }
public static void Main() { // create a TimeSpan instance, specifying the hours, minutes, // and seconds int hours = 4; int minutes = 12; int seconds = 10; TimeSpan myTimeSpan = new TimeSpan(hours, minutes, seconds); Console.WriteLine("myTimeSpan = " + myTimeSpan); // create a TimeSpan instance, specifying the days, hours, minutes, // and seconds int days = 1; TimeSpan myTimeSpan2 = new TimeSpan(days, hours, minutes, seconds); Console.WriteLine("myTimeSpan2 = " + myTimeSpan2); // create a TimeSpan instance, specifying the days, hours, minutes, // seconds, and milliseconds int milliseconds = 20; TimeSpan myTimeSpan3 = new TimeSpan(days, hours, minutes, seconds, milliseconds); Console.WriteLine("myTimeSpan3 = " + myTimeSpan3); // create a TimeSpan instance, specifying the number of ticks long ticks = 300; TimeSpan myTimeSpan4 = new TimeSpan(ticks); Console.WriteLine("myTimeSpan4 = " + myTimeSpan4); // display the properties for myTimeSpan Console.WriteLine("myTimeSpan.Days = " + myTimeSpan.Days); Console.WriteLine("myTimeSpan.Hours = " + myTimeSpan.Hours); Console.WriteLine("myTimeSpan.Minutes = " + myTimeSpan.Minutes); Console.WriteLine("myTimeSpan.Seconds = " + myTimeSpan.Seconds); Console.WriteLine("myTimeSpan.Milliseconds = " + myTimeSpan.Milliseconds); Console.WriteLine("myTimeSpan.Ticks = " + myTimeSpan.Ticks); Console.WriteLine("myTimeSpan.TotalDays = " + myTimeSpan.TotalDays); Console.WriteLine("myTimeSpan.TotalHours = " + myTimeSpan.TotalHours); Console.WriteLine("myTimeSpan.TotalMinutes = " + myTimeSpan.TotalMinutes); Console.WriteLine("myTimeSpan.TotalSeconds = " + myTimeSpan.TotalSeconds); Console.WriteLine("myTimeSpan.TotalMilliseconds = " + myTimeSpan.TotalMilliseconds); // use the FromDays(), FromHours(), FromMinutes(), FromSeconds(), // FromMilliseconds(), and FromTicks() methods to create new // TimeSpan instances TimeSpan myTimeSpan5 = TimeSpan.FromDays(5); Console.WriteLine("TimeSpan.FromDays(5) = " + myTimeSpan5); TimeSpan myTimeSpan6 = TimeSpan.FromHours(10); Console.WriteLine("TimeSpan.FromHours(10) = " + myTimeSpan6); TimeSpan myTimeSpan7 = TimeSpan.FromMinutes(30); Console.WriteLine("TimeSpan.FromMinutes(30) = " + myTimeSpan7); TimeSpan myTimeSpan8 = TimeSpan.FromSeconds(15); Console.WriteLine("TimeSpan.FromSeconds(15) = " + myTimeSpan8); TimeSpan myTimeSpan9 = TimeSpan.FromMilliseconds(200); Console.WriteLine("TimeSpan.FromMilliseconds(200) = " + myTimeSpan9); TimeSpan myTimeSpan10 = TimeSpan.FromTicks(500); Console.WriteLine("TimeSpan.FromTicks(500) = " + myTimeSpan10); // use the Parse() method to convert strings to TimeSpan instances TimeSpan myTimeSpan11 = TimeSpan.Parse("8:10:30"); Console.WriteLine("TimeSpan.Parse(\"8:10:30\") = " + myTimeSpan11); TimeSpan myTimeSpan12 = TimeSpan.Parse("1.8:10:30.1234567"); Console.WriteLine("TimeSpan.Parse(\"1.8:10:30.1234567\") = " + myTimeSpan12); // use the Add() method to add a TimeSpan instance to another TimeSpan myTimeSpan13 = new TimeSpan(1, 10, 13); TimeSpan myTimeSpan14 = new TimeSpan(2, 6, 10); TimeSpan myTimeSpan15 = myTimeSpan13.Add(myTimeSpan14); Console.WriteLine("myTimeSpan13 = " + myTimeSpan13); Console.WriteLine("myTimeSpan14 = " + myTimeSpan14); Console.WriteLine("myTimeSpan15 = " + myTimeSpan15); // use the Subtract() method to subtract a TimeSpan instance // from another myTimeSpan15 = myTimeSpan13.Subtract(myTimeSpan14); Console.WriteLine("myTimeSpan15 = " + myTimeSpan15); // use the Duration() method to add two TimeSpan instances Console.WriteLine("myTimeSpan15.Duration() = " + myTimeSpan15.Duration()); // use the Negate() method to add two TimeSpan instances Console.WriteLine("myTimeSpan15.Negate() = " + myTimeSpan15.Negate()); Console.WriteLine("myTimeSpan14.Negate() = " + myTimeSpan14.Negate()); }
}
</source>
Look at the min and max date/time values
<source lang="csharp">
using System; using System.Globalization; class MainClass {
public static void Main() { Console.WriteLine("Min Date: {0}", DateTime.MinValue.ToString()); Console.WriteLine("Max Date: {0}", DateTime.MaxValue.ToString()); }
}
</source>
Measures the time taken to add some numbers
<source lang="csharp"> /* Mastering Visual C# .NET by Jason Price, Mike Gunderloy Publisher: Sybex; ISBN: 0782129110
- /
/*
Example9_6.cs measures the time taken to add some numbers
- /
using System; public class Example9_6 {
public static void Main() { // create a DateTime object and set it to the // current date and time DateTime start = DateTime.Now; // add numbers using a for loop long total = 0; for (int count = 0; count < 1000000; count++) { total += count; } // subtract the current date and time from the start, // storing the difference in a TimeSpan TimeSpan timeTaken = DateTime.Now - start; // display the number of milliseconds taken to add the numbers Console.WriteLine("Milliseconds = " + timeTaken.Milliseconds); // display the total of the added numbers Console.WriteLine("total = " + total); }
}
</source>
new DateTime( 29)
<source lang="csharp">
using System; class MainClass { public static void Main() { DateTime dt = new DateTime(1900, 2, 29); } } </source>
new DateTime( 29, new JulianCalendar())
<source lang="csharp"> using System; using System.Globalization; class MainClass {
public static void Main() { DateTime dt = new DateTime(1900, 2, 29, new JulianCalendar()); }
}
</source>
Offset of DateTime
<source lang="csharp"> using System; public class MainClass {
public static void Main() { DateTimeOffset local = DateTimeOffset.Now; DateTimeOffset utc = local.ToUniversalTime(); Console.WriteLine(local.Offset); // -06:00:00 (in Central America) Console.WriteLine(utc.Offset); // 00:00:00 Console.WriteLine(local == utc); // True //To include the Offset in the comparison, you must use the EqualsExact method: Console.WriteLine(local.EqualsExact(utc)); // False }
}
</source>
Output DateTime object
<source lang="csharp"> using System; using System.Globalization; public class DatesApp {
public static void Main(string[] args) { DateTime dt = DateTime.Now; Console.WriteLine(dt); Console.WriteLine("date = {0}, time = {1}\n",dt.Date, dt.TimeOfDay); }
}
</source>
Parse and ParseExact
<source lang="csharp">
using System; class MainClass { public static void Main(string[] args) { DateTime dt1 = DateTime.Parse("Sep 2005"); Console.WriteLine(dt1); DateTime dt2 = DateTime.Parse("Monday 5 September 2005 14:15:33"); Console.WriteLine(dt2); DateTime dt3 = DateTime.Parse("5, 9,05"); Console.WriteLine(dt3); DateTime dt4 = DateTime.Parse("5/9/2005 14:15:33"); Console.WriteLine(dt4); DateTime dt5 = DateTime.Parse("2:15 PM"); Console.WriteLine(dt5); DateTime dt6 = DateTime.ParseExact("2:13:30 PM", "h:mm:ss tt", null); Console.WriteLine(dt6); DateTime dt7 = DateTime.ParseExact("Mon, 05 Sep 2005 14:13:30 GMT","ddd, dd MMM yyyy HH":"mm":"ss "GMT"", null); Console.WriteLine(dt7); DateTime dt8 = DateTime.ParseExact("September 05", "MMMM dd", null); Console.WriteLine(dt8); } } </source>
Specify Kind DateTime
<source lang="csharp"> using System; public class MainClass {
public static void Main() { DateTime d = new DateTime(2000, 12, 12); DateTime utc = DateTime.SpecifyKind(d, DateTimeKind.Utc); Console.WriteLine(utc); }
}
</source>
use the Add() method to add a TimeSpan to a DateTime
<source lang="csharp"> using System; class MainClass {
public static void Main() { TimeSpan myTimeSpan = new TimeSpan(1, 2, 4, 10); DateTime myDateTime6 = DateTime.Parse("1/13/2004 23:10:30"); DateTime myDateTime7 = myDateTime6.Add(myTimeSpan); Console.WriteLine("myTimeSpan = " + myTimeSpan); Console.WriteLine("myDateTime6.Add(myTimeSpan) = " + myDateTime7); }
}
</source>
use the AddYears(), AddMonths(), AddDays(), AddMinutes(), and AddSeconds() methods to add periods to a DateTime
<source lang="csharp"> using System; class MainClass {
public static void Main() { DateTime myDateTime9 = new DateTime(2004, 1, 1); Console.WriteLine("Initial myDateTime9 = " + myDateTime9); myDateTime9 = myDateTime9.AddYears(1); myDateTime9 = myDateTime9.AddMonths(5); myDateTime9 = myDateTime9.AddDays(3); myDateTime9 = myDateTime9.AddMinutes(30); myDateTime9 = myDateTime9.AddSeconds(15); Console.WriteLine("Final myDateTime9 = " + myDateTime9); }
}
</source>
use the Compare() method to compare DateTime instances
<source lang="csharp"> using System; class MainClass {
public static void Main() { DateTime myDateTime = DateTime.Now; DateTime myDateTime2 = DateTime.UtcNow; DateTime myDateTime3 = new DateTime(2004, 1, 13); DateTime myDateTime4 = new DateTime(2004, 1, 14); Console.WriteLine("myDateTime3 = " + myDateTime3); Console.WriteLine("myDateTime4 = " + myDateTime4); int intResult = DateTime.rupare(myDateTime3, myDateTime4); Console.WriteLine("DateTime.rupare(myDateTime3,myDateTime4) = " + DateTime.rupare(myDateTime, myDateTime2)); }
}
</source>
use the DaysInMonth() method to retrieve the number of days in a particular month and year
<source lang="csharp">
using System; class MainClass {
public static void Main() { int days = DateTime.DaysInMonth(2004, 1); Console.WriteLine("DateTime.DaysInMonth(2004, 1) = " + days); }
}
</source>
use the Equals() method to compare DateTime instances
<source lang="csharp"> using System; class MainClass {
public static void Main() { DateTime myDateTime3 = new DateTime(2004, 1, 13); DateTime myDateTime4 = new DateTime(2004, 1, 14); bool boolResult = DateTime.Equals(myDateTime3, myDateTime4); Console.WriteLine("DateTime.Equals(myDateTime3,myDateTime4) = " + boolResult); boolResult = myDateTime3.Equals(myDateTime4); Console.WriteLine("myDateTime3.Equals(myDateTime4) is " + boolResult); }
}
</source>
use the IsLeapYear() method to determine if a particular year is a leap year
<source lang="csharp">
using System; class MainClass {
public static void Main() { bool boolResult = DateTime.IsLeapYear(2004); Console.WriteLine("DateTime.IsLeapYear(2004) = " + boolResult); }
}
</source>
use the Now and UtcNow properties to get the currrent date and time
<source lang="csharp"> using System; class MainClass {
public static void Main() { Console.WriteLine("DateTime.Now = " + DateTime.Now); Console.WriteLine("DateTime.UtcNow = " + DateTime.UtcNow); DateTime myDateTime = DateTime.Now; Console.WriteLine("myDateTime = " + myDateTime); DateTime myDateTime2 = DateTime.UtcNow; Console.WriteLine("myDateTime = " + myDateTime); }
}
</source>
use the overloaded addition operator (+) to add a TimeSpan to a DateTime
<source lang="csharp"> using System; class MainClass {
public static void Main() { TimeSpan myTimeSpan = new TimeSpan(1, 2, 4, 10); DateTime myDateTime6 = DateTime.Parse("1/13/2004 23:10:30"); DateTime myDateTime8 = myDateTime6 + myTimeSpan; Console.WriteLine("myDateTime6 + myTimeSpan = " + myDateTime8); }
}
</source>
use the overloaded less than operator (
<source lang="csharp"> using System; class MainClass {
public static void Main() { DateTime myDateTime3 = new DateTime(2004, 1, 13); DateTime myDateTime4 = new DateTime(2004, 1, 14); bool boolResult = myDateTime3 < myDateTime4; Console.WriteLine("myDateTime3 < myDateTime4 is " + boolResult); }
}
</source>
use the overloaded subtraction operator (-) to subtract a TimeSpan from a DateTime
<source lang="csharp"> using System; class MainClass {
public static void Main() { TimeSpan myTimeSpan = new TimeSpan(1, 2, 4, 10); DateTime myDateTime6 = DateTime.Parse("1/13/2004 23:10:30"); DateTime myDateTime8 = myDateTime6 - myTimeSpan; Console.WriteLine("myDateTime6 - myTimeSpan = " + myDateTime8); }
}
</source>
use the Parse() method to convert strings to DateTime instances
<source lang="csharp"> using System; class MainClass {
public static void Main() { DateTime myDateTime5 = DateTime.Parse("1/13/2004"); DateTime myDateTime6 = DateTime.Parse("1/13/2004 23:10:30"); Console.WriteLine("myDateTime5 = " + myDateTime5); Console.WriteLine("myDateTime6 = " + myDateTime6);
}
}
</source>
use the Subtract() method to subtract a TimeSpan from a DateTime
<source lang="csharp"> using System; class MainClass {
public static void Main() { TimeSpan myTimeSpan = new TimeSpan(1, 2, 4, 10); DateTime myDateTime6 = DateTime.Parse("1/13/2004 23:10:30"); DateTime myDateTime7 = myDateTime6.Subtract(myTimeSpan); Console.WriteLine("myDateTime6.Subtract(myTimeSpan) = " + myDateTime7);
}
}
</source>
What day of the month is this?
<source lang="csharp"> using System; using System.Collections.Generic; using System.Text; class Program {
static void Main(string[] args) { DateTime dt = new DateTime(2004, 10, 17); Console.WriteLine("The day of {0} is {1}", dt.Date, dt.DayOfWeek); }
}
</source>