Directory.GetLastAccessTime(String) 方法

定義

命名空間:

System.IO

組件:

System.Runtime.dll

來源:

Directory.cs

傳回指定檔案或目錄上次被存取的日期和時間。

public:
 static DateTime GetLastAccessTime(System::String ^ path);

public static DateTime GetLastAccessTime (string path);

static member GetLastAccessTime : string -> DateTime

Public Shared Function GetLastAccessTime (path As String) As DateTime

參數

path

String

要取得其存取日期和時間資訊的檔案或目錄。

傳回

DateTime

結構，設定為指定之檔案或目錄上次被存取的日期和時間。 這個值以本地時間表示。

例外狀況

UnauthorizedAccessException

呼叫端沒有必要的權限。

ArgumentException

.NET Framework 和 2.1 之前的 .NET Core 版本：path是長度為零的字串、只包含空格符，或包含一或多個無效字元。 您可以使用 GetInvalidPathChars() 方法查詢無效字元。

ArgumentNullException

path 為 null。

PathTooLongException

指定的路徑、檔案名稱，或兩者都超出系統定義的長度上限。

NotSupportedException

path 參數的格式無效。

範例

下列範例示範如何使用 GetLastAccessTime。

using namespace System;
using namespace System::IO;
int main()
{
   try
   {
      String^ path = "c:\\MyDir";
      if (  !Directory::Exists( path ) )
      {
         Directory::CreateDirectory( path );
      }
      Directory::SetLastAccessTime( path, DateTime(1985,5,4) );
      
      // Get the creation time of a well-known directory.
      DateTime dt = Directory::GetLastAccessTime( path );
      Console::WriteLine( "The last access time for this directory was {0}", dt );
      
      // Update the last access time.
      Directory::SetLastAccessTime( path, DateTime::Now );
      dt = Directory::GetLastAccessTime( path );
      Console::WriteLine( "The last access time for this directory 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:\MyDir";
            if (!Directory.Exists(path))
            {
                Directory.CreateDirectory(path);
            }
            Directory.SetLastAccessTime(path, new DateTime(1985,5,4));

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

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

open System
open System.IO

try
    let path = @"c:\MyDir"
    if not (Directory.Exists path) then
        Directory.CreateDirectory path |> ignore

    Directory.SetLastAccessTime(path, DateTime(1985, 5, 4))

    // Get the creation time of a well-known directory.
    let dt = Directory.GetLastAccessTime path
    printfn $"The last access time for this directory was {dt}"
    
    // Update the last access time.
    Directory.SetLastAccessTime(path, DateTime.Now)
    let dt = Directory.GetLastAccessTime path
    printfn $"The last access time for this directory was {dt}"

with e ->
    printfn $"The process failed: {e}"

Imports System.IO

Public Class Test
    Public Shared Sub Main()
        Try
            Dim path As String = "c:\MyDir"
            If Directory.Exists(path) = False Then
                Directory.CreateDirectory(path)
            End If
            Directory.SetLastAccessTime(path, New DateTime(1985, 5, 4))

            'Get the access time of a well-known directory.
            Dim dt As DateTime = Directory.GetLastAccessTime(path)
            Console.WriteLine("The last access time for this directory was {0}", dt)

            'Update the last access time.
            Directory.SetLastAccessTime(path, DateTime.Now)
            dt = Directory.GetLastAccessTime(path)
            Console.WriteLine("The last access time for this directory was {0}", dt)

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

備註

注意

這個方法可能會傳回不正確的值，因為它會使用操作系統可能不會持續更新其值的原生函式。

這個方法與 File.GetLastAccessTime相同。

如果 參數中所述的 path 目錄不存在，此方法會傳回 12：00 午夜，1601 A.D. (C.E.) 國際標準時間 (UTC) ，調整為當地時間。

允許 path 參數指定相對或絕對路徑資訊。 相對路徑資訊會解譯為相對於目前工作目錄。 若要取得目前的工作目錄，請參閱 GetCurrentDirectory。

參數的 path 區分大小寫會對應至程式代碼執行所在的文件系統。 例如，在NTFS上不區分大小寫 (預設Windows檔案系統) 和Linux檔案系統上區分大小寫。

如需一般 I/O 工作的清單，請參閱 一般 I/O 工作。

另請參閱

• FileSystemWatcher
• 檔案和資料流 I/O
• 作法：讀取檔案中的文字
• 作法：將文字寫入檔案