FileStream.CanWrite FileStream.CanWrite FileStream.CanWrite FileStream.CanWrite Property

Definición

Obtiene un valor que indica si la secuencia actual admite escritura.Gets a value that indicates whether the current stream supports writing.

public:
 virtual property bool CanWrite { bool get(); };
public override bool CanWrite { get; }
member this.CanWrite : bool
Public Overrides ReadOnly Property CanWrite As Boolean

Valor de propiedad

Es true si la secuencia admite escritura; es false si la secuencia está cerrada o se abrió con acceso de solo lectura.true if the stream supports writing; false if the stream is closed or was opened with read-only access.

Ejemplos

En el ejemplo siguiente se CanWrite usa la propiedad para comprobar si una secuencia admite escritura.The following example uses the CanWrite property to check whether a stream supports writing.

using namespace System;
using namespace System::IO;
using namespace System::Text;

int main()
{
   String^ path = "c:\\temp\\MyTest.txt";
   
   // Ensure that the file is readonly.
   File::SetAttributes( path, static_cast<FileAttributes>(File::GetAttributes( path ) | FileAttributes::ReadOnly) );
   
   //Create the file.
   FileStream^ fs = gcnew FileStream( path,FileMode::OpenOrCreate,FileAccess::Read );
   try
   {
      if ( fs->CanWrite )
      {
         Console::WriteLine( "The stream for file {0} is writable.", path );
      }
      else
      {
         Console::WriteLine( "The stream for file {0} is not writable.", path );
      }
   }
   finally
   {
      if ( fs )
         delete (IDisposable^)fs;
   }
}
using System;
using System.IO;
using System.Text;

class Test 
{
	
    public static void Main() 
    {
        string path = @"c:\temp\MyTest.txt";

        // Ensure that the file is readonly.
        File.SetAttributes(path, File.GetAttributes(path) | FileAttributes.ReadOnly);

        //Create the file.
        using (FileStream fs = new FileStream (path, FileMode.OpenOrCreate, FileAccess.Read)) 
        {
            if (fs.CanWrite) 
            {
                Console.WriteLine("The stream for file {0} is writable.", path);
            } 
            else 
            {
                Console.WriteLine("The stream for file {0} is not writable.", path);
            }
        }
    }
}
Imports System
Imports System.IO

Public Class Test

    Public Shared Sub Main()
        Dim path As String = "c:\temp\MyTest.txt"

        'Ensure that the file is readonly.
        File.SetAttributes(path, File.GetAttributes(path) Or FileAttributes.ReadOnly)

        'Create the file.
        Dim fs As FileStream = New FileStream(path, FileMode.OpenOrCreate, FileAccess.Read)

        If fs.CanWrite Then
            Console.WriteLine("The stream connected to {0} is writable.", path)
        Else
            Console.WriteLine("The stream connected to {0} is not writable.", path)
        End If
        fs.Close()
    End Sub
End Class

El siguiente es un ejemplo de uso CanWrite de la propiedad.The following is an example using the CanWrite property. La salida de este código es "se puede escribir en el archivo. txt".The output of this code is "MyFile.txt is writable." Para obtener el mensaje de salida "se puede escribir en y leer el parámetro", cambie el FileAccess parámetro a ReadWrite en el FileStream constructor.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::Write );
   if ( fs->CanRead && fs->CanWrite )
   {
      Console::WriteLine( "MyFile.txt can be both written to and read from." );
   }
   else
   {
      Console::WriteLine( "MyFile.txt is 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.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.");
        }
    }
}
Imports System
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.")
        ElseIf fs.CanWrite Then
            Console.WriteLine("MyFile.txt is writable.")
        End If
    End Sub
End Class

Comentarios

Si una clase derivada de Stream no admite la escritura, una llamada a SetLength, Write, BeginWriteo WriteByte produce una NotSupportedExceptionexcepción.If a class derived from Stream does not support writing, a call to SetLength, Write, BeginWrite, or WriteByte throws a NotSupportedException.

Si el flujo está cerrado, esta propiedad devuelve false.If the stream is closed, this property returns false.

Se aplica a

Consulte también: