Directory.SetLastWriteTimeUtc(String, DateTime) Metoda

Definice

Obor názvů:

System.IO

Sestavení:

System.Runtime.dll

Zdroj:

Directory.cs

Nastaví datum a čas ve formátu UTC (Coordinated Universal Time), do kterého byl adresář naposledy zapsán.

public:
 static void SetLastWriteTimeUtc(System::String ^ path, DateTime lastWriteTimeUtc);

public static void SetLastWriteTimeUtc (string path, DateTime lastWriteTimeUtc);

static member SetLastWriteTimeUtc : string * DateTime -> unit

Public Shared Sub SetLastWriteTimeUtc (path As String, lastWriteTimeUtc As DateTime)

Parametry

path

String

Cesta k adresáři.

lastWriteTimeUtc

DateTime

Datum a čas posledního zápisu adresáře. Tato hodnota je vyjádřena v čase UTC.

Výjimky

FileNotFoundException

path nebyl nalezen (například adresář neexistuje nebo je na nenamapované jednotce).

DirectoryNotFoundException

path nebyl nalezen (například adresář neexistuje nebo je na nenamapované jednotce).

ArgumentException

.NET Framework a .NET Core verze starší než 2.1: path je řetězec nulové délky, obsahuje pouze prázdné znaky nebo obsahuje jeden nebo více neplatných znaků. Pomocí metody můžete zadat dotaz na neplatné znaky GetInvalidPathChars() .

ArgumentNullException

path je null.

PathTooLongException

Zadaná cesta, název souboru nebo obojí překračují maximální délku definovanou systémem.

UnauthorizedAccessException

Volající nemá požadované oprávnění.

PlatformNotSupportedException

Aktuální operační systém není systém Windows NT nebo novější.

ArgumentOutOfRangeException

lastWriteTimeUtc určuje hodnotu mimo rozsah kalendářních dat nebo časů povolených pro tuto operaci.

Příklady

Následující příklad ukazuje rozdíly ve výstupu při použití výstupu koordinovaného univerzálního času (UTC).

// This sample shows the differences between dates from methods that use
//coordinated universal time (UTC) format and those that do not.
using namespace System;
using namespace System::IO;
int main()
{
   
   // Set the directory.
   String^ n = "C:\\test\\newdir";
   
   //Create two variables to use to set the time.
   DateTime dtime1 = DateTime(2002,1,3);
   DateTime dtime2 = DateTime(1999,1,1);
   
   //Create the directory.
   try
   {
      Directory::CreateDirectory( n );
   }
   catch ( IOException^ e ) 
   {
      Console::WriteLine( e );
   }

   
   //Set the creation and last access times to a variable DateTime value.
   Directory::SetCreationTime( n, dtime1 );
   Directory::SetLastAccessTimeUtc( n, dtime1 );
   
   // Print to console the results.
   Console::WriteLine( "Creation Date: {0}", Directory::GetCreationTime( n ) );
   Console::WriteLine( "UTC creation Date: {0}", Directory::GetCreationTimeUtc( n ) );
   Console::WriteLine( "Last write time: {0}", Directory::GetLastWriteTime( n ) );
   Console::WriteLine( "UTC last write time: {0}", Directory::GetLastWriteTimeUtc( n ) );
   Console::WriteLine( "Last access time: {0}", Directory::GetLastAccessTime( n ) );
   Console::WriteLine( "UTC last access time: {0}", Directory::GetLastAccessTimeUtc( n ) );
   
   //Set the last write time to a different value.
   Directory::SetLastWriteTimeUtc( n, dtime2 );
   Console::WriteLine( "Changed last write time: {0}", Directory::GetLastWriteTimeUtc( n ) );
}

// Obviously, since this sample deals with dates and times, the output will vary
// depending on when you run the executable. Here is one example of the output:
//Creation Date: 1/3/2002 12:00:00 AM
//UTC creation Date: 1/3/2002 8:00:00 AM
//Last write time: 12/31/1998 4:00:00 PM
//UTC last write time: 1/1/1999 12:00:00 AM
//Last access time: 1/2/2002 4:00:00 PM
//UTC last access time: 1/3/2002 12:00:00 AM
//Changed last write time: 1/1/1999 12:00:00 AM

// This sample shows the differences between dates from methods that use
//coordinated universal time (UTC) format and those that do not.
using System;
using System.IO;

namespace IOSamples
{
  public class DirectoryUTCTime
  {
    public static void Main()
    {
    // Set the directory.
      string n = @"C:\test\newdir";
        //Create two variables to use to set the time.
      DateTime dtime1 = new DateTime(2002, 1, 3);
      DateTime dtime2 = new DateTime(1999, 1, 1);

    //Create the directory.
      try
      {
          Directory.CreateDirectory(n);
      }
      catch (IOException e)
      {
          Console.WriteLine(e);
      }

    //Set the creation and last access times to a variable DateTime value.
      Directory.SetCreationTime(n, dtime1);
      Directory.SetLastAccessTimeUtc(n, dtime1);

        // Print to console the results.
      Console.WriteLine("Creation Date: {0}", Directory.GetCreationTime(n));
      Console.WriteLine("UTC creation Date: {0}", Directory.GetCreationTimeUtc(n));
      Console.WriteLine("Last write time: {0}", Directory.GetLastWriteTime(n));
      Console.WriteLine("UTC last write time: {0}", Directory.GetLastWriteTimeUtc(n));
      Console.WriteLine("Last access time: {0}", Directory.GetLastAccessTime(n));
      Console.WriteLine("UTC last access time: {0}", Directory.GetLastAccessTimeUtc(n));

        //Set the last write time to a different value.
      Directory.SetLastWriteTimeUtc(n, dtime2);
      Console.WriteLine("Changed last write time: {0}", Directory.GetLastWriteTimeUtc(n));
    }
  }
}
// Obviously, since this sample deals with dates and times, the output will vary
// depending on when you run the executable. Here is one example of the output:
//Creation Date: 1/3/2002 12:00:00 AM
//UTC creation Date: 1/3/2002 8:00:00 AM
//Last write time: 12/31/1998 4:00:00 PM
//UTC last write time: 1/1/1999 12:00:00 AM
//Last access time: 1/2/2002 4:00:00 PM
//UTC last access time: 1/3/2002 12:00:00 AM
//Changed last write time: 1/1/1999 12:00:00 AM

// This sample shows the differences between dates from methods that use
//coordinated universal time (UTC) format and those that do not.
open System
open System.IO

// Set the directory.
let n = @"C:\test\newdir"
//Create two variables to use to set the time.
let dtime1 = DateTime(2002, 1, 3)
let dtime2 = DateTime(1999, 1, 1)

//Create the directory.
try
    Directory.CreateDirectory n |> ignore
with :? IOException as e ->
    printfn $"{e}"

//Set the creation and last access times to a variable DateTime value.
Directory.SetCreationTime(n, dtime1)
Directory.SetLastAccessTimeUtc(n, dtime1)

// Print to console the results.
printfn $"Creation Date: {Directory.GetCreationTime n}"
printfn $"UTC creation Date: {Directory.GetCreationTimeUtc n}"
printfn $"Last write time: {Directory.GetLastWriteTime n}"
printfn $"UTC last write time: {Directory.GetLastWriteTimeUtc n}"
printfn $"Last access time: {Directory.GetLastAccessTime n}"
printfn $"UTC last access time: {Directory.GetLastAccessTimeUtc n}"

//Set the last write time to a different value.
Directory.SetLastWriteTimeUtc(n, dtime2)
printfn $"Changed last write time: {Directory.GetLastWriteTimeUtc n}"
// Obviously, since this sample deals with dates and times, the output will vary
// depending on when you run the executable. Here is one example of the output:
//Creation Date: 1/3/2002 12:00:00 AM
//UTC creation Date: 1/3/2002 8:00:00 AM
//Last write time: 12/31/1998 4:00:00 PM
//UTC last write time: 1/1/1999 12:00:00 AM
//Last access time: 1/2/2002 4:00:00 PM
//UTC last access time: 1/3/2002 12:00:00 AM
//Changed last write time: 1/1/1999 12:00:00 AM

' This sample shows the differences between dates from methods that use
'coordinated universal time (UTC) format and those that do not.
Imports System.IO



Public Class DirectoryUTCTime
   
   Public Shared Sub Main()
      ' Set the directory.
      Dim n As String = "C:\test\newdir"
      'Create two variables to use to set the time.
      Dim dtime1 As New DateTime(2002, 1, 3)
      Dim dtime2 As New DateTime(1999, 1, 1)
      
      'Create the directory.
      Try
         Directory.CreateDirectory(n)
      Catch e As IOException
         Console.WriteLine(e)
      End Try
      
      'Set the creation and last access times to a variable DateTime value.
      Directory.SetCreationTime(n, dtime1)
      Directory.SetLastAccessTimeUtc(n, dtime1)
      
      ' Print to console the results.
      Console.WriteLine("Creation Date: {0}", Directory.GetCreationTime(n))
      Console.WriteLine("UTC creation Date: {0}", Directory.GetCreationTimeUtc(n))
      Console.WriteLine("Last write time: {0}", Directory.GetLastWriteTime(n))
      Console.WriteLine("UTC last write time: {0}", Directory.GetLastWriteTimeUtc(n))
      Console.WriteLine("Last access time: {0}", Directory.GetLastAccessTime(n))
      Console.WriteLine("UTC last access time: {0}", Directory.GetLastAccessTimeUtc(n))
      
      'Set the last write time to a different value.
      Directory.SetLastWriteTimeUtc(n, dtime2)
      Console.WriteLine("Changed last write time: {0}", Directory.GetLastWriteTimeUtc(n))
   End Sub
End Class

' Since this sample deals with dates and times, the output will vary
' depending on when you run the executable. Here is one example of the output:

' Creation Date: 1/3/2002 12:00:00 AM
' UTC creation Date: 1/3/2002 8:00:00 AM
' Last write time: 12/31/1998 4:00:00 PM
' UTC last write time: 1/1/1999 12:00:00 AM
' Last access time: 1/2/2002 4:00:00 PM
' UTC last access time: 1/3/2002 12:00:00 AM
' Changed last write time: 1/1/1999 12:00:00 AM

Poznámky

Parametr path může zadat relativní nebo absolutní informace o cestě. Informace o relativní cestě jsou vykládány jako relativní k aktuálnímu pracovnímu adresáři. Pokud chcete získat aktuální pracovní adresář, přečtěte si téma GetCurrentDirectory.

Rozlišování velkých a malých písmen parametru path odpovídá systému souborů, na kterém je kód spuštěn. Například v systému souborů NTFS (výchozí systém souborů Windows) se nerozlišují malá a velká písmena a v systémech souborů Linux.

Seznam běžných vstupně-výstupních úloh najdete v tématu Běžné vstupně-výstupní úlohy.

Viz také

• FileSystemWatcher
• Vstupně-výstupní operace souborů a Stream
• Postupy: Čtení textu ze souboru
• Postupy: Zápis textu do souboru