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DateTime.ToUniversalTime Method

Converts the value of the current DateTime object to Coordinated Universal Time (UTC).

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

'Declaration
Public Function ToUniversalTime As DateTime
'Usage
Dim instance As DateTime
Dim returnValue As DateTime

returnValue = instance.ToUniversalTime
public DateTime ToUniversalTime ()
public function ToUniversalTime () : DateTime

Return Value

A DateTime object whose Kind property is Utc, and whose value is the UTC equivalent to the value of the current DateTime object, or MaxValue if the converted value is too large to be represented by a DateTime object, or MinValue if the converted value is too small to be represented by a DateTime object.

The UTC time is equal to the local time minus the UTC offset. For more information about the UTC offset, see TimeZone.GetUtcOffset. The conversion also takes into account the daylight saving time rule that applies to the time represented by the current DateTime object.

Starting with the .NET Framework version 2.0, the value returned by the ToUniversalTime method is determined by the Kind property of the current DateTime object. The following table describes the possible results.

Kind

Results

Utc

No conversion is performed.

Local

The current DateTime object is converted to UTC.

Unspecified

The current DateTime object is assumed to be a local time, and the conversion is performed as if Kind were Local.

The value returned by this conversion is a DateTime object whose Kind property is Utc. Consequently, a valid result is returned even if ToUniversalTime is applied repeatedly to the same DateTime object.

This method always uses the local time zone when making calculations.

The following code example demonstrates the ToUniversalTime method.

System.Console.WriteLine("Enter a date and time.")
Dim strDateTime As String
strDateTime = System.Console.ReadLine()

Dim localDateTime As System.DateTime
Try
   localDateTime = System.DateTime.Parse(strDateTime)
Catch exp As System.FormatException
   System.Console.WriteLine("Invalid format.")
End Try

Dim univDateTime As System.DateTime
univDateTime = localDateTime.ToUniversalTime()

System.Console.WriteLine("{0} local time is {1} universal time.", _
                           localDateTime, _
                           univDateTime)

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

Try
   univDateTime = System.DateTime.Parse(strDateTime)
Catch exp As System.FormatException
   System.Console.WriteLine("Invalid format.")
End Try

localDateTime = univDateTime.ToLocalTime()

System.Console.WriteLine("{0} universal time is {1} local time.", _
                           univDateTime, _
                           localDateTime)

System.Console.WriteLine("Enter a date and time.");
String strDateTime = System.Console.ReadLine();

System.DateTime localDateTime;
try {
    localDateTime = System.DateTime.Parse(strDateTime);
}
catch (System.FormatException exp) {
    System.Console.WriteLine("Invalid format.");
    return;
}
System.DateTime univDateTime = localDateTime.ToUniversalTime();
System.Console.WriteLine("{0} local time is {1} universal time.", 
    localDateTime, univDateTime);
System.Console.WriteLine("Enter a date and time in universal time.");
strDateTime = System.Console.ReadLine();
try {
    univDateTime = System.DateTime.Parse(strDateTime);
}
catch (System.FormatException exp) {
    System.Console.WriteLine("Invalid format.");
    return;
}
localDateTime = univDateTime.ToLocalTime();
System.Console.WriteLine("{0} universal time is {1} local time.", 
    univDateTime, localDateTime);

The following code example uses the SpecifyKind method to demonstrate how the Kind property influences the ToLocalTime and ToUniversalTime conversion methods.


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

Class Sample
    Public Shared Sub Main() 
        ' Get the date and time for the current moment, adjusted 
        ' to the local time zone.
        Dim saveNow As DateTime = DateTime.Now
        
        ' Get the date and time for the current moment expressed 
        ' as coordinated universal time (UTC).
        Dim saveUtcNow As DateTime = DateTime.UtcNow
        Dim myDt As DateTime
        
        ' 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)
    End Sub 'Main
    
    ' 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 Shared datePatt As String = "M/d/yyyy hh:mm:ss tt"
    
    Public Shared Sub Display(ByVal title As String, ByVal inputDt As DateTime) 
        Dim dispDt As DateTime = inputDt
        Dim dtString As String
        
        ' 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()
    End Sub 'Display
    
    
    ' Display the value and Kind property for DateTime.Now and DateTime.UtcNow.

    Public Shared Sub DisplayNow(ByVal title As String, ByVal inputDt As DateTime) 
        Dim dtString As String = inputDt.ToString(datePatt)
        Console.WriteLine("{0} {1}, Kind = {2}", title, dtString, inputDt.Kind)
    End Sub 'DisplayNow
End Class 'Sample

'
'This code example produces the following results:
'
'UtcNow: .......... 5/6/2005 09:34:42 PM, Kind = Utc
'Now: ............. 5/6/2005 02:34:42 PM, Kind = Local
'
'Utc: ............. 5/6/2005 02:34:42 PM, Kind = Utc
'  ToLocalTime:     5/6/2005 07:34:42 AM, Kind = Local
'  ToUniversalTime: 5/6/2005 02:34:42 PM, Kind = Utc
'
'Local: ........... 5/6/2005 02:34:42 PM, Kind = Local
'  ToLocalTime:     5/6/2005 02:34:42 PM, Kind = Local
'  ToUniversalTime: 5/6/2005 09:34:42 PM, Kind = Utc
'
'Unspecified: ..... 5/6/2005 02:34:42 PM, Kind = Unspecified
'  ToLocalTime:     5/6/2005 07:34:42 AM, Kind = Local
'  ToUniversalTime: 5/6/2005 09:34:42 PM, Kind = Utc
'

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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