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.NET Framework Class Library
BinaryReaderReadByte 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)
Syntax
Public Overridable Function ReadByte As [%$TOPIC/e9fay22f_en-us_VS_110_1_0_0_0_0%]
public virtual [%$TOPIC/e9fay22f_en-us_VS_110_1_0_1_0_0%] ReadByte()
public:
virtual [%$TOPIC/e9fay22f_en-us_VS_110_1_0_2_0_0%] ReadByte()
abstract ReadByte : unit -> [%$TOPIC/e9fay22f_en-us_VS_110_1_0_3_0_0%]  
override ReadByte : unit -> [%$TOPIC/e9fay22f_en-us_VS_110_1_0_3_0_1%]

Return Value

Type: SystemByte
The next byte read from the current stream.
Exceptions
ExceptionCondition
EndOfStreamException

The end of the stream is reached.

ObjectDisposedException

The stream is closed.

IOException

An I/O error occurs.

Remarks

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

  • ISCII

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

Examples

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.

Imports System
Imports System.IO

Public Class BinaryRW

    Shared Sub Main()

        Dim i As Integer = 0

        ' Create random data to write to the stream. 
        Dim writeArray(1000) As Byte 
        Dim randomGenerator As New Random()
        randomGenerator.NextBytes(writeArray)

        Dim binWriter As New BinaryWriter(New MemoryStream())
        Dim binReader As New BinaryReader(binWriter.BaseStream)

        Try 

            ' Write the data to the stream.
            Console.WriteLine("Writing the data.")
            For i = 0 To writeArray.Length - 1
                binWriter.Write(writeArray(i))
            Next 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 To writeArray.Length - 1
                If binReader.ReadByte() <> writeArray(i) Then
                    Console.WriteLine("Error writing the data.")
                    Return 
                End If 
            Next i
            Console.WriteLine("The data was written and verified.")

        ' Catch the EndOfStreamException and write an error message. 
        Catch ex As EndOfStreamException
            Console.WriteLine("Error writing the data: {0}", _
                ex.GetType().Name)
        End Try 

    End Sub 
End Class
using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        int i = 0;

        // Create random data to write to the stream. 
        byte[] writeArray = new byte[1000];
        new Random().NextBytes(writeArray);

        BinaryWriter binWriter = new BinaryWriter(new MemoryStream());
        BinaryReader binReader = 
            new BinaryReader(binWriter.BaseStream);

        try
        {
            // 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;
                }
            }
            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);
        }
    }
}
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 );
   try
   {

      // 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 );
   }

}
Version Information

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 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

.NET for Windows Store apps

Supported in: Windows 8

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1
Platforms

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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