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BinaryReader.Read Method (Byte(), Int32, Int32)

Reads count bytes from the stream with index as the starting point in the byte array.

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

'Declaration
Public Overridable Function Read ( _
	buffer As Byte(), _
	index As Integer, _
	count As Integer _
) As Integer
'Usage
Dim instance As BinaryReader 
Dim buffer As Byte()
Dim index As Integer 
Dim count As Integer 
Dim returnValue As Integer 

returnValue = instance.Read(buffer, index, _
	count)

Parameters

buffer
Type: System.Byte()

The buffer to read data into.

index
Type: System.Int32

The starting point in the buffer at which to begin reading into the buffer.

count
Type: System.Int32

The number of characters to read.

Return Value

Type: System.Int32
The number of characters read into buffer. This might be less than the number of bytes requested if that many bytes are not available, or it might be zero if the end of the stream is reached.

ExceptionCondition
ArgumentException

The buffer length minus index is less than count.

-or-

The number of decoded characters to read is greater than count. This can happen if a Unicode decoder returns fallback characters or a surrogate pair.

ArgumentNullException

buffer is Nothing.

ArgumentOutOfRangeException

index or count is negative.

ObjectDisposedException

The stream is closed.

IOException

An I/O error occurs.

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

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

The following example shows how to write binary data using memory as a backing store. It then displays a message to the console that indicates whether the data was written correctly.

Imports System
Imports System.IO

Public Class BinaryRW

    Shared Sub Main()

        Const upperBound As Integer = 1000

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

        Dim binWriter As New BinaryWriter(New MemoryStream())

        ' Write the data to the stream.
        Console.WriteLine("Writing the data.")
        binWriter.Write(dataArray, 0, dataArray.Length)

        ' Create the reader using the stream from the writer. 
        Dim binReader As New BinaryReader(binWriter.BaseStream)

        ' Set Position to the beginning of the stream.
        binReader.BaseStream.Position = 0

        ' Read and verify the data. 
        Dim verifyArray(upperBound) As Byte
        If binReader.Read(verifyArray, 0, dataArray.Length) _
            <> dataArray.Length Then

            Console.WriteLine("Error writing the data.")
            Return 
        End If 
        For i As Integer =  0 To upperBound
            If verifyArray(i) <> dataArray(i) Then
                Console.WriteLine("Error writing the data.")
                Return 
            End If 
        Next i
        Console.WriteLine("The data was written and verified.")

    End Sub 
End Class

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

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