Stream.CanRead Property (System.IO)

CanRead Property

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This page is specific to

Microsoft Visual Studio 2008/.NET Framework 3.5

Other versions are also available for the following:

.NET Framework Class Library

Stream..::.CanRead Property

When overridden in a derived class, gets a value indicating whether the current stream supports reading.

Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)

Syntax

Visual Basic (Declaration)

Public MustOverride ReadOnly Property CanRead As Boolean

Visual Basic (Usage)

Dim instance As Stream
Dim value As Boolean

value = instance.CanRead

public abstract bool CanRead { get; }

Visual C++

public:
virtual property bool CanRead {
    bool get () abstract;
}

JScript

public abstract function get CanRead () : boolean

Property Value

Type: System..::.Boolean
true if the stream supports reading; otherwise, false.

Remarks

For an example of creating a file and writing text to a file, see How to: Write Text to a File. For an example of reading text from a file, see How to: Read Text from a File. For an example of reading from and writing to a binary file, see How to: Read and Write to a Newly Created Data File.

If a class derived from Stream does not support reading, calls to the Read, ReadByte, and BeginRead methods throw a NotSupportedException.

If the stream is closed, this property returns false.

Examples

The following is an example of using the CanRead property.

Visual Basic

Imports System
Imports System.IO

Class TestRW

    Public Shared Sub Main()
        Dim fs As New FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read)
        If fs.CanRead And fs.CanWrite Then
            Console.WriteLine("MyFile.txt can be both written to and read from.")
        Else
            If fs.CanRead Then
                Console.WriteLine("MyFile.txt is not writable.")
            End If
        End If
    End Sub
End Class

using System;
using System.IO;

class TestRW 
{
    public static void Main(String[] args)
    {
        FileStream fs = new FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read);
        if (fs.CanRead && fs.CanWrite)
        {
            Console.WriteLine("MyFile.txt can be both written to and read from.");
        }
        else if (fs.CanRead)
        {
            Console.WriteLine("MyFile.txt is not writable.");
        }
    }
}

Visual C++

using namespace System;
using namespace System::IO;
int main( void )
{
   FileStream^ fs = gcnew FileStream( "MyFile.txt",FileMode::OpenOrCreate,FileAccess::Read );
   if ( fs->CanRead && fs->CanWrite )
   {
      Console::WriteLine( "MyFile.txt can be both written to and read from." );
   }
   else
   {
      Console::WriteLine( "MyFile.txt is not writable" );
   }

   return 0;
}

JScript

 import System;
 import System.IO;

class TestRW 
{
   public static function Main() : void 
   {

         var fs : FileStream = new FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read);
         if (fs.CanRead && fs.CanWrite)
         {
            Console.WriteLine("MyFile.txt can be both written to and read from.");
         }
         else if (fs.CanRead)
         {
            Console.WriteLine("MyFile.txt is not writable.");
      }
   }
}
TestRW.Main();

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Reference

Stream Class

Stream Members

System.IO Namespace

Other Resources

File and Stream I/O

How to: Read Text from a File

How to: Write Text to a File