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DateTime.ToFileTime Method

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

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

public long ToFileTime ()
public long ToFileTime ()
public function ToFileTime () : long

Return Value

The value of the current DateTime object expressed as a Windows file time.

Exception typeCondition

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.

Previous versions of the ToFileTime method assume the current DateTime object is a local time. Starting with the.NET Framework version 2.0, the ToFileTime 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 local time.

The following code example demonstrates the ToFileTime method.

static void Main(string[] args)
{
    System.Console.WriteLine("Enter the file path:");
    string filePath = System.Console.ReadLine();

    if (System.IO.File.Exists(filePath)) {
        System.DateTime fileCreationDateTime = 
            System.IO.File.GetCreationTime(filePath);

        long fileCreationFileTime = fileCreationDateTime.ToFileTime();

        System.Console.WriteLine("{0} in file time is {1}.",
                                 fileCreationDateTime,
                                 fileCreationFileTime);
    } 
    else {
        System.Console.WriteLine("{0} is an invalid file", filePath);
    }
}

public static void main(String[] args)
{
    System.Console.WriteLine("Enter the file path:");
    String filePath = System.Console.ReadLine();

    if (System.IO.File.Exists(filePath)) {
        System.DateTime fileCreationDateTime = System.IO.File.
            GetCreationTime(filePath);
        long fileCreationFileTime = fileCreationDateTime.ToFileTime();
        System.Console.WriteLine("{0} in file time is {1}.", 
        fileCreationDateTime, (Int64)fileCreationFileTime);
    }
    else {
        System.Console.WriteLine("{0} is an invalid file", filePath);
    }
} //main

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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