File.SetLastWriteTime Method

Reference

Definition

Namespace:: System.IO

Assemblies:: netstandard.dll, System.Runtime.dll

Assemblies:: mscorlib.dll, System.IO.FileSystem.dll

Assemblies:: netstandard.dll, System.IO.FileSystem.dll

Assemblies:: netstandard.dll, System.IO.FileSystem.dll, System.Runtime.dll

Assembly:: System.IO.FileSystem.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Overloads

SetLastWriteTime(SafeFileHandle, DateTime)	Sets the date and time that the specified file or directory was last written to.
SetLastWriteTime(String, DateTime)	Sets the date and time that the specified file was last written to.

SetLastWriteTime(SafeFileHandle, DateTime)

Source:: File.cs

Source:: File.cs

Source:: File.cs

Sets the date and time that the specified file or directory was last written to.

public:
 static void SetLastWriteTime(Microsoft::Win32::SafeHandles::SafeFileHandle ^ fileHandle, DateTime lastWriteTime);

public static void SetLastWriteTime(Microsoft.Win32.SafeHandles.SafeFileHandle fileHandle, DateTime lastWriteTime);

static member SetLastWriteTime : Microsoft.Win32.SafeHandles.SafeFileHandle * DateTime -> unit

Public Shared Sub SetLastWriteTime (fileHandle As SafeFileHandle, lastWriteTime As DateTime)

Parameters

fileHandle: SafeFileHandle

A SafeFileHandle to the file or directory for which to set the last write date and time information.

lastWriteTime: DateTime

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

Exceptions

ArgumentNullException

fileHandle is null.

ArgumentOutOfRangeException

lastWriteTime specifies a value outside the range of dates, times, or both permitted for this operation.

UnauthorizedAccessException

The caller does not have the required permission.

IOException

An I/O error occurred while performing the operation.

Applies to

.NET 10 and other versions

Product	Versions
.NET	7, 8, 9, 10

SetLastWriteTime(String, DateTime)

Source:: File.cs

Source:: File.cs

Source:: File.cs

Sets the date and time that the specified file was last written to.

public:
 static void SetLastWriteTime(System::String ^ path, DateTime lastWriteTime);

public static void SetLastWriteTime(string path, DateTime lastWriteTime);

static member SetLastWriteTime : string * DateTime -> unit

Public Shared Sub SetLastWriteTime (path As String, lastWriteTime As DateTime)

Parameters

path: String

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

lastWriteTime: DateTime

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

Exceptions

ArgumentException

.NET Framework and .NET Core versions older than 2.1: path is a zero-length string, contains only white space, or contains one or more invalid characters. You can query for invalid characters by using the GetInvalidPathChars() method.

ArgumentNullException

path is null.

PathTooLongException

The specified path, file name, or both exceed the system-defined maximum length.

FileNotFoundException

The specified path was not found.

UnauthorizedAccessException

The caller does not have the required permission.

NotSupportedException

path is in an invalid format.

ArgumentOutOfRangeException

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

Examples

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

using namespace System;
using namespace System::IO;
int main()
{
   try
   {
      String^ path = "c:\\Temp\\MyTest.txt";
      if (  !File::Exists( path ) )
      {
         File::Create( path );
      }
      else
      {
         
         // Take an action that will affect the write time.
         File::SetLastWriteTime( path, DateTime(1985,4,3) );
      }
      
      // Get the creation time of a well-known directory.
      DateTime dt = File::GetLastWriteTime( path );
      Console::WriteLine( "The last write time for this file was {0}.", dt );
      
      // Update the last write time.
      File::SetLastWriteTime( path, DateTime::Now );
      dt = File::GetLastWriteTime( path );
      Console::WriteLine( "The last write time for this file was {0}.", dt );
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "The process failed: {0}", e );
   }

}

using System;
using System.IO;

class Test
{
    public static void Main()
    {
        try
        {
            string path = @"c:\Temp\MyTest.txt";
            if (!File.Exists(path))
            {
                File.Create(path);
            }
            else
            {
                // Take an action that will affect the write time.
                File.SetLastWriteTime(path, new DateTime(1985,4,3));
            }

            // Get the creation time of a well-known directory.
            DateTime dt = File.GetLastWriteTime(path);
            Console.WriteLine("The last write time for this file was {0}.", dt);
            
            // Update the last write time.
            File.SetLastWriteTime(path, DateTime.Now);
            dt = File.GetLastWriteTime(path);
            Console.WriteLine("The last write time for this file was {0}.", dt);
        }
        catch (Exception e)
        {
            Console.WriteLine("The process failed: {0}", e.ToString());
        }
    }
}

open System
open System.IO

try
    let path = @"c:\Temp\MyTest.txt"

    if File.Exists path |> not then
        File.Create path |> ignore
    else
        // Take an action that will affect the write time.
        File.SetLastWriteTime(path, DateTime(1985, 4, 3))

    // Get the creation time of a well-known directory.
    let dt = File.GetLastWriteTime path
    printfn $"The last write time for this file was {dt}."

    // Update the last write time.
    File.SetLastWriteTime(path, DateTime.Now)
    let dt = File.GetLastWriteTime path
    printfn $"The last write time for this file was {dt}."
with
| e -> printfn $"The process failed: {e}"

Imports System.IO
Imports System.Text

Public Class Test
    Public Shared Sub Main()
        Try
            Dim path As String = "c:\Temp\MyTest.txt"

            If File.Exists(path) = False Then
                File.Create(path)
            Else
                ' Take an action that will affect the write time.
                File.SetLastWriteTime(path, New DateTime(1985, 4, 3))
            End If

            ' Get the creation time of a well-known directory.
            Dim dt As DateTime = File.GetLastWriteTime(path)
            Console.WriteLine("The last write time for this file was {0}.", dt)

            ' Update the last write time.
            File.SetLastWriteTime(path, DateTime.Now)
            dt = File.GetLastWriteTime(path)
            Console.WriteLine("The last write time for this file was {0}.", dt)

        Catch e As Exception
            Console.WriteLine("The process failed: {0}", e.ToString())
        End Try
    End Sub
End Class

Remarks

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.

Applies to

.NET 10 and other versions

Product	Versions
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	1.3, 1.4, 1.6, 2.0, 2.1
UWP	10.0

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File.SetLastWriteTime Method

Definition

Overloads

SetLastWriteTime(SafeFileHandle, DateTime)

Parameters

Exceptions

Applies to

SetLastWriteTime(String, DateTime)

Parameters

Exceptions

Examples

Remarks

See also

Applies to

Additional resources