Stream.CanRead Propriedade

Definição

Quando substituído em uma classe derivada, obtém um valor que indica se o fluxo atual dá suporte à leitura.When overridden in a derived class, gets a value indicating whether the current stream supports reading.

public:
 abstract property bool CanRead { bool get(); };
public abstract bool CanRead { get; }
member this.CanRead : bool
Public MustOverride ReadOnly Property CanRead As Boolean

Valor da propriedade

true se o fluxo der suporte à leitura; caso contrário, false.true if the stream supports reading; otherwise, false.

Exemplos

Veja a seguir um exemplo de como usar CanRead a propriedade.The following is an example of using the CanRead property.

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

Comentários

Se uma classe derivada de Stream não oferecer suporte à leitura, as chamadas Readpara ReadByteos métodos BeginRead , e lançarão um 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 for fechado, essa propriedade retornará false.If the stream is closed, this property returns false.

Aplica-se a

Veja também