BinaryReader.ReadByte Method

Reference

Definition

Namespace:: System.IO

Assemblies:: mscorlib.dll, System.IO.dll

Assemblies:: netstandard.dll, System.Runtime.dll

Assembly:: System.IO.dll

Assembly:: System.Runtime.Extensions.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Source:: BinaryReader.cs

Source:: BinaryReader.cs

Source:: BinaryReader.cs

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

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

public:
 virtual System::Byte ReadByte();

public virtual byte ReadByte();

abstract member ReadByte : unit -> byte
override this.ReadByte : unit -> byte

Public Overridable Function ReadByte () As Byte

Returns

Byte

The next byte read from the current stream.

Exceptions

EndOfStreamException

The end of the stream is reached.

ObjectDisposedException

The stream is closed.

IOException

An I/O error occurred.

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.

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 );
   }

}

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);
        }
    }
}

open System
open System.IO

// Create random data to write to the stream.
let writeArray = Array.zeroCreate<byte> 1000
Random().NextBytes writeArray

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

try
    // Write the data to the stream.
    printfn "Writing the data."
    for i = 0 to writeArray.Length - 1 do
        binWriter.Write writeArray[i]

    // Set the stream position to the beginning of the stream.
    binReader.BaseStream.Position <- 0

    let mutable failed = false
    // Read and verify the data from the stream.
    for i = 0 to writeArray.Length - 1 do
        if binReader.ReadByte() <> writeArray[i] then
            printfn "Error writing the data."
            failed <- true
    if not failed then
        printfn "The data was written and verified."

// Catch the EndOfStreamException and write an error message.
with :? EndOfStreamException as e ->
    printfn $"Error writing the data.\n{e.GetType().Name}"

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

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.

Applies to

Product	Versions
.NET	Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9, 10
.NET Framework	1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard	1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 2.0, 2.1
UWP	10.0

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