Stream.CanWrite Propriedade

Definição

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

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

Valor da propriedade

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

Exemplos

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

using namespace System;
using namespace System::IO;
int main()
{
   FileStream^ fs = gcnew FileStream( "MyFile.txt",FileMode::OpenOrCreate,FileAccess::Write );
   if ( fs->CanRead && fs->CanWrite )
   {
      Console::WriteLine( "MyFile.txt can be both written to and read from." );
   }
   else
   if ( fs->CanWrite )
   {
      Console::WriteLine( "MyFile.txt is writable." );
   }
}

//This code outputs "MyFile.txt is writable."
//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 System;
using System.IO;

class TestRW 
{
  public static void Main(String[] args)
  { 
    FileStream fs = new FileStream("MyFile.txt", FileMode.OpenOrCreate,
       FileAccess.Write);
    if (fs.CanRead && fs.CanWrite) {
        Console.WriteLine("MyFile.txt can be both written to and read from.");
    }
    else if (fs.CanWrite) {
        Console.WriteLine("MyFile.txt is writable.");
    }
  }
}
//This code outputs "MyFile.txt is writable."
//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.
Imports System.IO

Class TestRW    

    Public Shared Sub Main()
        Dim fs As New FileStream("MyFile.txt", FileMode.OpenOrCreate, _
           FileAccess.Write)
        If fs.CanRead And fs.CanWrite Then
            Console.WriteLine("MyFile.txt can be both written to and read from.")
        Else
            If fs.CanWrite Then
                Console.WriteLine("MyFile.txt is writable.")
            End If
        End If
    End Sub
End Class

'This code outputs "MyFile.txt is writable."
'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.

Comentários

Se uma classe derivada de Stream não der suporte à gravação, uma chamada para Write, BeginWriteou WriteByte lançará uma NotSupportedException.If a class derived from Stream does not support writing, a call to Write, BeginWrite, or WriteByte throws a NotSupportedException. Nesses casos, a Flush normalmente é implementada como um método vazio para garantir a compatibilidade total com outros tipos de Stream, já que ele é válido para liberar um fluxo somente leitura.In such cases, Flush is typically implemented as an empty method to ensure full compatibility with other Stream types since it's valid to flush a read-only stream.

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

Aplica-se a

Veja também