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File.SetLastAccessTime Method

Sets the date and time the specified file was last accessed.

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

public static void SetLastAccessTime(
	string path,
	DateTime lastAccessTime


Type: System.String

The file for which to set the access date and time information.

Type: System.DateTime

A DateTime containing the value to set for the last access date and time of path. This value is expressed in local time.


path is a zero-length string, contains only white space, or contains one or more invalid characters as defined by InvalidPathChars.


path is null.


The specified path, file name, or both exceed the system-defined maximum length. For example, on Windows-based platforms, paths must be less than 248 characters, and file names must be less than 260 characters.


The specified path was not found.


The caller does not have the required permission.


path is in an invalid format.


lastAccessTime specifies a value outside the range of dates or times permitted for this operation.

The path parameter is permitted to specify relative or absolute path information. Relative path information is interpreted as relative to the current working directory. To obtain the current working directory, see GetCurrentDirectory.

For a list of common I/O tasks, see Common I/O Tasks.

The following example checks the file system for the specified file, creating it if necessary, and then sets and gets the last access time.

using System;
using System.IO;

class Test 
    public static void Main() 
            string path = @"c:\Temp\MyTest.txt";

            if (!File.Exists(path)) 
                // Update the last access time.	
            File.SetLastAccessTime(path, new DateTime(1985,5,4));

            // Get the creation time of a well-known directory.
            DateTime dt = File.GetLastAccessTime(path);
            Console.WriteLine("The last access time for this file was {0}.", dt);
            // Update the last access time.
            File.SetLastAccessTime(path, DateTime.Now);
            dt = File.GetLastAccessTime(path);
            Console.WriteLine("The last access time for this file was {0}.", dt);

        catch (Exception e) 
            Console.WriteLine("The process failed: {0}", e.ToString());

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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