Stream.CanWrite Proprietà

Definizione

Quando ne viene eseguito l'override in una classe derivata, ottiene un valore che indica se il flusso corrente supporta la scrittura.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

Valore della proprietà

Boolean

true se il flusso supporta la scrittura; in caso contrario, false.true if the stream supports writing; otherwise, false.

Esempio

Di seguito è riportato un esempio di utilizzo della CanWrite Proprietà.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.

Commenti

Se una classe derivata da non Stream supporta la scrittura, una chiamata a Write , BeginWrite o WriteByte genera un'eccezione NotSupportedException .If a class derived from Stream does not support writing, a call to Write, BeginWrite, or WriteByte throws a NotSupportedException. In questi casi, Flush viene in genere implementato come metodo vuoto per garantire la compatibilità completa con altri Stream tipi poiché è valido per scaricare un flusso di sola lettura.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.

Si applica a

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