C# DateTime.ToUniversalTime方法代碼示例

//引入命名空間
using System;

class Example
{
    static void Main()
    {
        DateTime localDateTime, univDateTime;
        
        Console.WriteLine("Enter a date and time.");
        string strDateTime = Console.ReadLine();

        try {
            localDateTime = DateTime.Parse(strDateTime);
            univDateTime = localDateTime.ToUniversalTime();
    
            Console.WriteLine("{0} local time is {1} universal time.",
                                localDateTime,
                                    univDateTime); 
        }
        catch (FormatException) {
            Console.WriteLine("Invalid format.");
            return;
        }

        Console.WriteLine("Enter a date and time in universal time.");
        strDateTime = Console.ReadLine();

        try {
            univDateTime = DateTime.Parse(strDateTime);
            localDateTime = univDateTime.ToLocalTime();
    
            Console.WriteLine("{0} universal time is {1} local time.",
                                     univDateTime,
                                     localDateTime); 
        }
        catch (FormatException) {
            Console.WriteLine("Invalid format.");
            return;
        }
    }
}
// The example displays output like the following when run on a 
// computer whose culture is en-US in the Pacific Standard Time zone:
//     Enter a date and time.
//     12/10/2015 6:18 AM
//     12/10/2015 6:18:00 AM local time is 12/10/2015 2:18:00 PM universal time.
//     Enter a date and time in universal time.
//     12/20/2015 6:42:00
//     12/20/2015 6:42:00 AM universal time is 12/19/2015 10:42:00 PM local time.

// This code example demonstrates the DateTime Kind, Now, and
// UtcNow properties, and the SpecifyKind(), ToLocalTime(), 
// and ToUniversalTime() methods.

using System;

class Sample 
{
    public static void Main() 
    {
// Get the date and time for the current moment, adjusted 
// to the local time zone.

    DateTime saveNow = DateTime.Now;

// Get the date and time for the current moment expressed 
// as coordinated universal time (UTC).

    DateTime saveUtcNow = DateTime.UtcNow;
    DateTime myDt;

// Display the value and Kind property of the current moment 
// expressed as UTC and local time.

    DisplayNow("UtcNow: ..........", saveUtcNow);
    DisplayNow("Now: .............", saveNow);
    Console.WriteLine();

// Change the Kind property of the current moment to 
// DateTimeKind.Utc and display the result.

    myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Utc);
    Display("Utc: .............", myDt);

// Change the Kind property of the current moment to 
// DateTimeKind.Local and display the result.

    myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Local);
    Display("Local: ...........", myDt);

// Change the Kind property of the current moment to 
// DateTimeKind.Unspecified and display the result.

    myDt = DateTime.SpecifyKind(saveNow, DateTimeKind.Unspecified);
    Display("Unspecified: .....", myDt);
    }

// Display the value and Kind property of a DateTime structure, the 
// DateTime structure converted to local time, and the DateTime 
// structure converted to universal time. 

    public static string datePatt = @"M/d/yyyy hh:mm:ss tt";
    public static void Display(string title, DateTime inputDt)
    {
    DateTime dispDt = inputDt;
    string dtString;

// Display the original DateTime.

    dtString = dispDt.ToString(datePatt);
    Console.WriteLine("{0} {1}, Kind = {2}", 
                      title, dtString, dispDt.Kind);

// Convert inputDt to local time and display the result. 
// If inputDt.Kind is DateTimeKind.Utc, the conversion is performed.
// If inputDt.Kind is DateTimeKind.Local, the conversion is not performed.
// If inputDt.Kind is DateTimeKind.Unspecified, the conversion is 
// performed as if inputDt was universal time.

    dispDt = inputDt.ToLocalTime();
    dtString = dispDt.ToString(datePatt);
    Console.WriteLine("  ToLocalTime:     {0}, Kind = {1}", 
                      dtString, dispDt.Kind);

// Convert inputDt to universal time and display the result. 
// If inputDt.Kind is DateTimeKind.Utc, the conversion is not performed.
// If inputDt.Kind is DateTimeKind.Local, the conversion is performed.
// If inputDt.Kind is DateTimeKind.Unspecified, the conversion is 
// performed as if inputDt was local time.

    dispDt = inputDt.ToUniversalTime();
    dtString = dispDt.ToString(datePatt);
    Console.WriteLine("  ToUniversalTime: {0}, Kind = {1}", 
                      dtString, dispDt.Kind);
    Console.WriteLine();
    }

// Display the value and Kind property for DateTime.Now and DateTime.UtcNow.

    public static void DisplayNow(string title, DateTime inputDt)
    {
    string dtString = inputDt.ToString(datePatt);
    Console.WriteLine("{0} {1}, Kind = {2}", 
                      title, dtString, inputDt.Kind);
    }
}

//引入命名空間
using System;

public class Example
{
   public static void Main()
   {
      DateTime date1 = new DateTime(2006, 3, 21, 2, 0, 0);
      
      Console.WriteLine(date1.ToUniversalTime());
      Console.WriteLine(TimeZoneInfo.ConvertTimeToUtc(date1));
      
      TimeZoneInfo tz = TimeZoneInfo.FindSystemTimeZoneById("Pacific Standard Time");  
      Console.WriteLine(TimeZoneInfo.ConvertTimeToUtc(date1, tz));     
   }
}
// The example displays the following output on Windows XP systems:
//       3/21/2006 9:00:00 AM
//       3/21/2006 9:00:00 AM
//       3/21/2006 10:00:00 AM