FileStream.CanSeek Proprietà

Definizione

Ottiene un valore che indica se il flusso corrente supporta la ricerca.Gets a value that indicates whether the current stream supports seeking.

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

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.true if the stream supports seeking; false if the stream is closed or if the FileStream was constructed from an operating-system handle such as a pipe or output to the console.

Esempi

Nell'esempio seguente viene utilizzata la proprietà CanSeek per verificare se un flusso supporta la ricerca.The following example uses the CanSeek property to check whether a stream supports seeking.

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);
            }
        }
    }
}
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, SetLength, Positione Seek generano un'NotSupportedException.If a class derived from Stream does not support seeking, calls to Length, SetLength, Position, and Seek throw a NotSupportedException.

Se il flusso è chiuso, questa proprietà restituisce false.If the stream is closed, this property returns false.

Si applica a

Vedi anche