ToFileTimeUtc Method

DateTime.ToFileTimeUtc Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

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

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

Public Function ToFileTimeUtc As Long

Return Value

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


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.

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 Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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