FileStream.CanRead FileStream.CanRead FileStream.CanRead FileStream.CanRead Property

Definição

Obtém um valor que indica se o fluxo atual dá suporte a leitura.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 da propriedade

true se o fluxo dá suporte à leitura; false se o fluxo está fechado ou foi aberto com acesso somente gravação.true if the stream supports reading; false if the stream is closed or was opened with write-only access.

Exemplos

O exemplo a seguir demonstra um uso do CanRead propriedade.The following example demonstrates a use of the CanRead property. A saída desse código é "Myfile. txt não é gravável."The output of this code is "MyFile.txt is not writable." Para obter a mensagem de saída "Myfile. txt pode ser gravados e lidos do.", altere a FileAccess parâmetro para ReadWrite no FileStream construtor.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
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

Comentários

Se uma classe derivada de Stream não dá suporte à leitura, chamadas para o Read, ReadByte, e BeginRead métodos geram uma NotSupportedException.If a class derived from Stream does not support reading, calls to the Read, ReadByte, and BeginRead methods throw a NotSupportedException.

Se o fluxo está fechado, essa propriedade retornará false.If the stream is closed, this property returns false.

Aplica-se a

Veja também