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.NET Development
.NET Framework 3.5
System.IO Namespace
File Class
File Methods
 GetLastWriteTime Method

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This page is specific to
Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:
.NET Framework Class Library
File..::.GetLastWriteTime Method

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

Namespace:  System.IO
Assembly:  mscorlib (in mscorlib.dll)
Visual Basic (Declaration)
Public Shared Function GetLastWriteTime ( _
    path As String _
) As DateTime
Visual Basic (Usage)
Dim path As String
Dim returnValue As DateTime

returnValue = File.GetLastWriteTime(path)
C#
public static DateTime GetLastWriteTime(
    string path
)
Visual C++
public:
static DateTime GetLastWriteTime(
    String^ path
)
JScript
public static function GetLastWriteTime(
    path : String
) : DateTime

Parameters

path
Type: System..::.String
The file or directory for which to obtain write date and time information.

Return Value

Type: System..::.DateTime
A DateTime structure set to the date and time that the specified file or directory was last written to. This value is expressed in local time.
ExceptionCondition
UnauthorizedAccessException

The caller does not have the required permission.

ArgumentException

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

ArgumentNullException

path is nullNothingnullptra null reference (Nothing in Visual Basic).

PathTooLongException

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.

NotSupportedException

path is in an invalid format.

If the file described in the path parameter does not exist, this method returns 12:00 midnight, January 1, 1601 A.D. (C.E.) Coordinated Universal Time (UTC), adjusted to local time.

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 demonstrates GetLastWriteTime.

Visual Basic
Imports System
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 some 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

C#
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());
        }
    }
}

Visual C++
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 );
   }

}


Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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File does not exist? Exception?      TheUndeadable   |   Edit   |   Show History
What happens if file does not exist?
Not immediately available after closing file      Terry Hutt   |   Edit   |   Show History
I have a problem when I overwrite a text file created with a StreamWriter. I close the streamwriter, dispose of it, and call GetLastWriteTime. It always returns the date/time the file I overwrote had
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