DateTime::ToUniversalTime Method
Converts the value of the current DateTime object to Coordinated Universal Time (UTC).
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Return Value
Type: System::DateTimeAn object whose Kind property is Utc, and whose value is one of the following: the UTC equivalent of the current DateTime value, or DateTime::MaxValue if the converted value is too large to be represented by a DateTime object, or DateTime::MinValue if the converted value is too small to be represented by a DateTime object.
The Coordinated Universal Time (UTC) is equal to the local time minus the UTC offset. The conversion also takes into account the daylight saving time rule that applies to the time represented by the current DateTime object.
Important Note: |
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The ToUniversalTime method recognizes only the current adjustment rule when converting from local time to UTC. As a result, conversions for periods before the current adjustment rule came into effect may not accurately reflect the difference between local time and UTC. |
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 |
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No conversion is performed. | |
The current DateTime object is converted to UTC. | |
The current DateTime object is assumed to be a local time, and the conversion is performed as if Kind were Local. |
Note: |
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The ToUniversalTime method converts a DateTime value from local time to UTC. To convert a time whose offset from UTC is known, use the ToUniversalTime method. |
If the date and time instance value is an ambiguous time, this method assumes that it is a standard time. (An ambiguous time is one that can map either to a standard time or to a daylight saving time in the local time zone) If the date and time instance value is an invalid time, this method simply subtracts the local time from the local time zone's UTC offset to return UTC. (An invalid time is one that does not exist because of the application of daylight saving time adjustment rules.)
Notes to CallersThe ToUniversalTime method is sometimes used to convert a local time to UTC, and subsequently to restore it by calling the ToLocalTime method. However, if the original time represents an invalid time in the local time zone, the two local time values will not be equal. For additional information and an example, see the ToLocalTime method.
The following example demonstrates the ToUniversalTime method.
The following example uses the SpecifyKind method to demonstrate how the Kind property influences the ToLocalTime and ToUniversalTime conversion methods.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
Important Note: