Stream.CanWrite Eigenschaft

  • Referenz

Definition

Namespace:
System.IO
Assembly:
System.IO.dll
Assembly:
System.Runtime.dll
Assembly:
mscorlib.dll
Assembly:
netstandard.dll
Quelle:
Stream.cs
Quelle:
Stream.cs
Quelle:
Stream.cs

Ruft beim Überschreiben in einer abgeleiteten Klasse einen Wert ab, der angibt, ob der aktuelle Stream Schreibvorgänge unterstützt.

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

Eigenschaftswert

Boolean

true, wenn der Stream Schreibvorgänge unterstützt, andernfalls false.

Beispiele

Im folgenden Beispiel wird die CanWrite -Eigenschaft verwendet.

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.

Hinweise

Wenn eine von Stream abgeleitete Klasse das Schreiben nicht unterstützt, löst ein Aufruf von Write, BeginWriteoder WriteByte einen aus NotSupportedException. In solchen Fällen wird in der Regel als leere Methode implementiert, um die vollständige Kompatibilität mit anderen Stream Typen sicherzustellen, da es gültig ist, Flush einen schreibgeschützten Stream zu leeren.

Gilt für:

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