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SetLastWriteTime Method

Directory.SetLastWriteTime Method

Sets the date and time a directory was last written to.

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

public static void SetLastWriteTime(
	string path,
	DateTime lastWriteTime


Type: System.String

The path of the directory.

Type: System.DateTime

The date and time the directory was last written to. This value is expressed in local time.


The specified path was not found.


path is a zero-length string, contains only white space, or contains one or more invalid characters. You can query for invalid characters with the GetInvalidPathChars method.


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 caller does not have the required permission.


The current operating system is not Windows NT or later.


lastWriteTime 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.

The path parameter is not case-sensitive.

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

Windows 95, Windows 98, Windows 98 Second Edition Platform Note: These operating systems do not support this method.

The following example demonstrates how to use SetLastWriteTime.

using System;
using System.IO;

class Test 
    public static void Main() 
            string path = @"c:\MyDir";
            if (!Directory.Exists(path)) 
                // Take an action that will affect the write time.
                Directory.SetLastWriteTime(path, new DateTime(1985,4,3));

            // Get the last write time of a well-known directory.
            DateTime dt = Directory.GetLastWriteTime(path);
            Console.WriteLine("The last write time for this directory was {0}", dt);
            //Update the last write time.
            Directory.SetLastWriteTime(path, DateTime.Now);
            dt = Directory.GetLastWriteTime(path);
            Console.WriteLine("The last write time for this directory 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

© 2015 Microsoft