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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)

Public Overridable Function ReadByte As Byte

Return Value

Type: System.Byte

The next byte read from the current stream.

Exception Condition

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.

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()

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


            ' Write the data to the stream.
            Console.WriteLine("Writing the data.")
            For i = 0 To writeArray.Length - 1
            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.")
                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}", _
        End Try

    End Sub
End Class

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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