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BinaryWriterWrite Method
 

Writes a byte array to the underlying stream.

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

Syntax
public virtual void Write(
	byte[] buffer
)
public:
virtual void Write(
	array<unsigned char>^ buffer
)
abstract Write : 
        buffer:byte[] -> unit
override Write : 
        buffer:byte[] -> unit
Public Overridable Sub Write (
	buffer As Byte()
)

Parameters

buffer
Type:

A byte array containing the data to write.

Exceptions
Exception Condition
IOException

An I/O error occurs.

ObjectDisposedException

The stream is closed.

ArgumentNullException

buffer is null.

Remarks

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.

using System;
using System.IO;

class BinaryRW
{
    static void Main()
    {
        const int arrayLength = 1000;

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

        BinaryWriter binWriter = new BinaryWriter(new MemoryStream());

        // Write the data to the stream.
        Console.WriteLine("Writing the data.");
        binWriter.Write(dataArray);

        // Create the reader using the stream from the writer.
        BinaryReader binReader = 
            new BinaryReader(binWriter.BaseStream);

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

        // Read and verify the data.
        byte[] verifyArray = binReader.ReadBytes(arrayLength);
        if(verifyArray.Length != arrayLength)
        {
            Console.WriteLine("Error writing the data.");
            return;
        }
        for(int i = 0; i < arrayLength; i++)
        {
            if(verifyArray[i] != dataArray[i])
            {
                Console.WriteLine("Error writing the data.");
                return;
            }
        }
        Console.WriteLine("The data was written and verified.");
    }
}
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)

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

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

        ' Read and verify the data.
        Dim verifyArray() As Byte = _
            binReader.ReadBytes(dataArray.Length)
        If verifyArray.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
using namespace System;
using namespace System::IO;
int main()
{
   const int arrayLength = 1000;

   // Create random data to write to the stream.
   array<Byte>^dataArray = gcnew array<Byte>(arrayLength);
   (gcnew Random)->NextBytes( dataArray );
   BinaryWriter^ binWriter = gcnew BinaryWriter( gcnew MemoryStream );

   // Write the data to the stream.
   Console::WriteLine(  "Writing the data." );
   binWriter->Write( dataArray );

   // Create the reader using the stream from the writer.
   BinaryReader^ binReader = gcnew BinaryReader( binWriter->BaseStream );

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

   // Read and verify the data.
   array<Byte>^verifyArray = binReader->ReadBytes( arrayLength );
   if ( verifyArray->Length != arrayLength )
   {
      Console::WriteLine( "Error writing the data." );
      return  -1;
   }

   for ( int i = 0; i < arrayLength; i++ )
   {
      if ( verifyArray[ i ] != dataArray[ i ] )
      {
         Console::WriteLine( "Error writing the data." );
         return  -1;
      }

   }
   Console::WriteLine( "The data was written and verified." );
}
Version Information
Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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