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Stream.CanRead Property

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

[Visual Basic]
Public MustOverride ReadOnly Property CanRead As Boolean
[C#]
public abstract bool CanRead {get;}
[C++]
public: __property virtual bool get_CanRead() = 0;
[JScript]
public abstract function get CanRead() : Boolean;

Property Value

true if the stream supports reading; otherwise, false.

Remarks

For an example of creating a file and writing text to a file, see Writing Text to a File. For an example of reading text from a file, see Reading Text from a File. For an example of reading from and writing to a binary file, see Reading and Writing 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.

Example

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

[C#] 
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.");
        }
    }
}

[C++] 
#using <mscorlib.dll>

using namespace System;
using namespace System::IO;

int main(void)
{
    FileStream * fs = new FileStream(S"MyFile.txt", FileMode::OpenOrCreate, FileAccess::Read);
    if ( fs->CanRead && fs->CanWrite )
    {
        Console::WriteLine(S"MyFile.txt can be both written to and read from.");
    } else {
        Console::WriteLine(S"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();

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework, Common Language Infrastructure (CLI) Standard

See Also

Stream Class | Stream Members | System.IO Namespace | Working with I/O | Reading Text from a File | Writing Text to a File

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