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

Definition

Ruft einen Wert ab, der angibt, ob der aktuelle Stream Schreibvorgänge unterstützt.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

Eigenschaftswert

true, wenn der Stream Schreibvorgänge unterstützt, false, wenn der Stream geschlossen ist oder mit schreibgeschütztem Zugriff geöffnet wurde.true if the stream supports writing; false if the stream is closed or was opened with read-only access.

Beispiele

Im folgenden Beispiel wird die CanWrite Eigenschaft zu überprüfen, ob ein Stream Schreibvorgänge unterstützt.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

Im folgenden finden Sie ein Beispiel mit der CanWrite Eigenschaft.The following is an example using the CanWrite property. Die Ausgabe dieses Codes ist "MyFile.txt geschrieben werden kann."The output of this code is "MyFile.txt is writable." Beim Abrufen der ausgabemeldung "MyFile.txt können sowohl in geschrieben und gelesen werden.", Ändern der FileAccess Parameter ReadWrite in die FileStream Konstruktor.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

Hinweise

Wenn eine Klasse von abgeleitet Stream unterstützt nicht das Schreiben, handelt es sich bei eines Aufrufs von SetLength, Write, BeginWrite, oder WriteByte löst eine NotSupportedException.If a class derived from Stream does not support writing, a call to SetLength, Write, BeginWrite, or WriteByte throws a NotSupportedException.

Wenn der Stream geschlossen ist, gibt diese Eigenschaft false.If the stream is closed, this property returns false.

Gilt für:

Siehe auch