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FileStream.CanSeek Proprietà

  • Riferimento

Definizione

Spazio dei nomi:
System.IO
Assembly:
mscorlib.dll, System.IO.FileSystem.dll
Assembly:
System.Runtime.dll
Assembly:
System.IO.FileSystem.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Origine:
FileStream.cs
Origine:
FileStream.cs
Origine:
FileStream.cs

Ottiene un valore che indica se il flusso corrente supporta la ricerca.

public:
 virtual property bool CanSeek { bool get(); };
public override bool CanSeek { get; }
member this.CanSeek : bool
Public Overrides ReadOnly Property CanSeek As Boolean

Valore della proprietà

Boolean

true se il flusso supporta la ricerca; false se il flusso viene chiuso o se FileStream è stato costruito da un handle del sistema operativo, ad esempio un pipe o un output di console.

Esempio

Nell'esempio seguente viene usata la proprietà per verificare se un flusso supporta la CanSeek ricerca.

using namespace System;
using namespace System::IO;
using namespace System::Text;

int main()
{
   String^ path = "c:\\temp\\MyTest.txt";
   
   // Delete the file if it exists.
   if ( File::Exists( path ) )
   {
      File::Delete( path );
   }

   //Create the file.
   FileStream^ fs = File::Create( path );
   try
   {
      if ( fs->CanSeek )
      {
         Console::WriteLine( "The stream connected to {0} is seekable.", path );
      }
      else
      {
         Console::WriteLine( "The stream connected to {0} is not seekable.", path );
      }
   }
   finally
   {
      if ( fs )
         delete (IDisposable^)fs;
   }
}

using System;
using System.IO;
using System.Text;

class Test
{
    
    public static void Main()
    {
        string path = @"c:\temp\MyTest.txt";

        // Delete the file if it exists.
        if (File.Exists(path))
        {
            File.Delete(path);
        }

        //Create the file.
        using (FileStream fs = File.Create(path))
        {
            if (fs.CanSeek)
            {
                Console.WriteLine("The stream connected to {0} is seekable.", path);
            }
            else
            {
                Console.WriteLine("The stream connected to {0} is not seekable.", path);
            }
        }
    }
}

open System.IO

let path = @"c:\temp\MyTest.txt"

// Delete the file if it exists.
if File.Exists path then
    File.Delete path


//Create the file.
do
    use fs = File.Create path

    if fs.CanSeek then
        printfn $"The stream connected to {path} is seekable."
    else
        printfn $"The stream connected to {path} is not seekable."

Imports System.IO

Public Class Test

    Public Shared Sub Main()
        Dim path As String = "c:\temp\MyTest.txt"

        ' Delete the file if it exists.
        If File.Exists(path) Then
            File.Delete(path)
        End If

        'Create the file.
        Dim fs As FileStream = File.Create(path)

        If fs.CanSeek Then
            Console.WriteLine("The stream connected to {0} is seekable.", path)
        Else
            Console.WriteLine("The stream connected to {0} is not seekable.", path)
        End If

        fs.Close()
    End Sub
End Class

Commenti

Se una classe derivata da Stream non supporta la ricerca, le chiamate a Length, SetLengthPosition, e Seek generano un NotSupportedExceptionoggetto .

Se il flusso viene chiuso, questa proprietà restituisce false.

Si applica a

Vedi anche