This documentation is archived and is not being maintained.

BinaryReader::ReadByte Method

Reads the next byte from the current stream and advances the current position of the stream by one byte.

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

virtual unsigned char ReadByte()

Return Value

Type: System::Byte
The next byte read from the current stream.


The end of the stream is reached.


The stream is closed.


An I/O error occurs.

BinaryReader does not restore the file position after an unsuccessful read.

Because of data formatting conflicts, using this method with the following encodings is not recommended:

  • UTF-7

  • ISO-2022-JP


For a list of common I/O tasks, see Common I/O Tasks.

The following code example shows how to write binary data using memory as a backing store, and then verify that the data was written correctly.

using namespace System;
using namespace System::IO;
int main()
   int i = 0;

   // Create random data to write to the stream.
   array<Byte>^writeArray = gcnew array<Byte>(1000);
   (gcnew Random)->NextBytes( writeArray );
   BinaryWriter^ binWriter = gcnew BinaryWriter( gcnew MemoryStream );
   BinaryReader^ binReader = gcnew BinaryReader( binWriter->BaseStream );

      // Write the data to the stream.
      Console::WriteLine( "Writing the data." );
      for ( i = 0; i < writeArray->Length; i++ )
         binWriter->Write( writeArray[ i ] );


      // Set the stream position to the beginning of the stream.
      binReader->BaseStream->Position = 0;

      // Read and verify the data from the stream.
      for ( i = 0; i < writeArray->Length; i++ )
         if ( binReader->ReadByte() != writeArray[ i ] )
            Console::WriteLine( "Error writing the data." );
            return  -1;

      Console::WriteLine( "The data was written and verified." );
   // Catch the EndOfStreamException and write an error message.
   catch ( EndOfStreamException^ e ) 
      Console::WriteLine( "Error writing the data.\n{0}", e->GetType()->Name );


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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