FileStream.CanRead Propiedad

Definición

Obtiene un valor que indica si la secuencia actual admite lectura.Gets a value that indicates whether the current stream supports reading.

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

Valor de propiedad

Boolean

Es true si la secuencia admite lectura; es false si la secuencia está cerrada o se abrió con acceso de solo escritura.true if the stream supports reading; false if the stream is closed or was opened with write-only access.

Ejemplos

En el siguiente ejemplo se muestra el uso de la CanRead propiedad.The following example demonstrates a use of the CanRead property. El resultado de este código es "MyFile.txt no es grabable".The output of this code is "MyFile.txt is not writable." Para obtener el mensaje de salida "MyFile.txt se pueden escribir y leer en.", cambie el FileAccess parámetro a ReadWrite en el FileStream constructor.To get the output message "MyFile.txt can be both written to and read from.", change the FileAccess parameter to ReadWrite in the FileStream constructor.

using namespace System;
using namespace System::IO;
int main( void )
{
   FileStream^ fs = gcnew FileStream( "MyFile.txt",FileMode::OpenOrCreate,FileAccess::Read );
   if ( fs->CanRead && fs->CanWrite )
   {
      Console::WriteLine( "MyFile.txt can be both written to and read from." );
   }
   else
   {
      Console::WriteLine( "MyFile.txt is not writable" );
   }

   return 0;
}

using System;
using System.IO;

class TestRW
{
    public static void Main(String[] args)
    {
        FileStream fs = new FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read);
        if (fs.CanRead && fs.CanWrite)
        {
            Console.WriteLine("MyFile.txt can be both written to and read from.");
        }
        else if (fs.CanRead)
        {
            Console.WriteLine("MyFile.txt is not writable.");
        }
    }
}
Imports System.IO

Class TestRW

    Public Shared Sub Main()
        Dim fs As New FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read)
        If fs.CanRead And fs.CanWrite Then
            Console.WriteLine("MyFile.txt can be both written to and read from.")
        Else
            If fs.CanRead Then
                Console.WriteLine("MyFile.txt is not writable.")
            End If
        End If
    End Sub
End Class

Comentarios

Si una clase derivada de no Stream admite la lectura, las llamadas a Read los ReadByte métodos, y BeginRead inician una excepción NotSupportedException .If a class derived from Stream does not support reading, calls to the Read, ReadByte, and BeginRead methods throw a NotSupportedException.

Si el flujo está cerrado, esta propiedad devuelve false .If the stream is closed, this property returns false.

Se aplica a