BinaryWriter::Write Method (Byte)


Writes an unsigned byte to the current stream and advances the stream position by one byte.

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

virtual void Write(
	unsigned char value


Type: System::Byte

The unsigned byte to write.

Exception Condition

An I/O error occurs.


The stream is closed.

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.

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 );

      // 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 );


Universal Windows Platform
Available since 8
.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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