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DateTime.ToFileTimeUtc Method

Updated: January 2010

Converts the value of the current DateTime object to a Windows file time.

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

public long ToFileTimeUtc()

Return Value

Type: System.Int64
The value of the current DateTime object expressed as a Windows file time.

ExceptionCondition
ArgumentOutOfRangeException

The resulting file time would represent a date and time before 12:00 midnight January 1, 1601 C.E. UTC.

A Windows file time is a 64-bit value that represents the number of 100-nanosecond intervals that have elapsed since 12:00 midnight, January 1, 1601 A.D. (C.E.) Coordinated Universal Time (UTC). Windows uses a file time to record when an application creates, accesses, or writes to a file.

Prior versions of the ToFileTimeUtc method assume the current DateTime object is a UTC time. Starting with the.NET Framework version 2.0, the ToFileTimeUtc method uses the Kind property to determine whether the current DateTime object is a local time, a UTC time, or an unspecified kind of time which is treated as a UTC time. If it is a local time, it converts the time to UTC before performing the conversion to a Windows file time.

Notes to Callers:

The ToFileTimeUtc method is sometimes used to convert a local time to UTC, and subsequently to restore it by calling the FromFileTimeUtc method followed by 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, see the ToLocalTime method.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

January 2010

Added the Notes for Callers section.

Content bug fix.

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