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BinaryWriter Class

Writes primitive types in binary to a stream and supports writing strings in a specific encoding.

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

[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public ref class BinaryWriter : IDisposable
/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
public class BinaryWriter implements IDisposable
SerializableAttribute 
ComVisibleAttribute(true) 
public class BinaryWriter implements IDisposable
Not applicable.

A derived class can override the methods of this class to give unique character encodings.

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

The following code example demonstrates how to store and retrieve application settings in a file.

using namespace System;
using namespace System::IO;
using namespace System::Security::Permissions;

// Store and retrieve application settings.
ref class AppSettings
{
private:
   static String^ fileName =  "AppSettings#@@#.dat";
   float aspectRatio;
   String^ lookupDir;
   int autoSaveTime;
   Boolean showStatusBar;

public:

   property float AspectRatio
   {
      float get()
      {
         return aspectRatio;
      }

      void set( float value )
      {
         aspectRatio = value;
      }

   }

   property String^ LookupDir
   {
      String^ get()
      {
         return lookupDir;
      }

      void set( String^ value )
      {
         lookupDir = value;
      }

   }

   property int AutoSaveTime
   {
      int get()
      {
         return autoSaveTime;
      }

      void set( int value )
      {
         autoSaveTime = value;
      }

   }

   property Boolean ShowStatusBar
   {
      Boolean get()
      {
         return showStatusBar;
      }

      void set( Boolean value )
      {
         showStatusBar = value;
      }

   }
   AppSettings()
   {

      // Create default application settings.
      aspectRatio = 1.3333F;
      lookupDir =  "C:\\AppDirectory";
      autoSaveTime = 30;
      showStatusBar = false;
      if ( File::Exists( fileName ) )
      {

         BinaryReader^ binReader = gcnew BinaryReader( File::Open( fileName, FileMode::Open ) );
         try
         {


            // If the file is not empty,
            // read the application settings.
            // Read 4 bytes into a buffer to
            // determine if the file is empty.
            array<Byte>^testArray = gcnew array<Byte>(3);
            int count = binReader->Read(testArray, 0, 3);
            if ( count != -1 )
            {
               aspectRatio = binReader->ReadSingle();
               lookupDir = binReader->ReadString();
               autoSaveTime = binReader->ReadInt32();
               showStatusBar = binReader->ReadBoolean();
               return;
            }
         }
         // If the end of the stream is reached before reading
         // the four data values, ignore the error and use the
         // default settings for the remaining values.
         catch ( EndOfStreamException^ e )
         {
            Console::WriteLine( "{0} caught and ignored. "
            "Using default values.", e->GetType()->Name );
         }
         finally
         {
            binReader->Close();
         }


      }
   }


   // Create a file and store the application settings.
   void Close()
   {

      BinaryWriter^ binWriter = gcnew BinaryWriter( File::Open( fileName, FileMode::Create ) );
      try
      {
         binWriter->Write( aspectRatio );
         binWriter->Write( lookupDir );
         binWriter->Write( autoSaveTime );
         binWriter->Write( showStatusBar );
      }
      finally
      {
         binWriter->Close();
      }


   }

};

int main()
{

   // Load application settings.
   AppSettings^ appSettings = gcnew AppSettings;
   array<Object^>^someObject = {appSettings->AspectRatio.ToString(),appSettings->LookupDir,appSettings->AutoSaveTime.ToString(),appSettings->ShowStatusBar.ToString()};
   Console::WriteLine( "App settings.\nAspect Ratio: {0}, "
   "Lookup directory: {1},\nAuto save time: {2} minutes, "
   "Show status bar: {3}\n", someObject );

   // Change the settings.
   appSettings->AspectRatio = 1.250F;
   appSettings->LookupDir =  "C:\\Temp";
   appSettings->AutoSaveTime = 10;
   appSettings->ShowStatusBar = true;

   // Save the new settings.
   appSettings->Close();
}


import System.*;
import System.IO.*;
import System.Security.Permissions.*;

class Test
{
    public static void main(String[] args)
    {
        // Load application settings.
        AppSettings appSettings = new AppSettings();
        Console.WriteLine("App settings.\nAspect Ratio: {0}, "
            + "Lookup directory: {1},\nAuto save time: {2} minutes, "
            + "Show status bar: {3}\n",
            new Object[]{System.Convert.ToString(appSettings.get_AspectRatio()),
            appSettings.get_LookupDir(),
            System.Convert.ToString(appSettings.get_AutoSaveTime()),
            System.Convert.ToString(appSettings.get_ShowStatusBar())});

        // Change the settings.
        appSettings.set_AspectRatio(1.25F);
        appSettings.set_LookupDir("C:\\Temp");
        appSettings.set_AutoSaveTime ( 10);
        appSettings.set_ShowStatusBar( true);

        // Save the new settings.
        appSettings.Close();
    } //main
} //Test

// Store and retrieve application settings.
class AppSettings
{
    private String fileName = "AppSettings#@@#.dat";
    private float aspectRatio;
    private String lookupDir;
    private int autoSaveTime;
    private boolean showStatusBar;

    /** @property
     */
    public float get_AspectRatio()
    {
        return aspectRatio ;
    }//get_AspectRatio

    /** @property
     */
    public void set_AspectRatio ( float value )
    {
        aspectRatio = value;
    }//set_AspectRatio

    /** @property
     */
    public String get_LookupDir()
    {
        return lookupDir ;
    }//get_LookupDir

    /** @property
     */
    public void set_LookupDir ( String value )
    {
        lookupDir = value;
    }//set_LookupDir

    /** @property
     */
    public int get_AutoSaveTime()
    {
        return autoSaveTime ;
    }//get_AutoSaveTime

    /** @property
     */
    public void set_AutoSaveTime ( int value )
    {
        autoSaveTime = value;
    }//set_AutoSaveTime

    /** @property
     */
    public boolean get_ShowStatusBar()
    {
        return showStatusBar ;
    }//get_ShowStatusBar

    /** @property
     */
    public void set_ShowStatusBar ( boolean value )
    {
        showStatusBar = value;
    }//set_ShowStatusBar

    public AppSettings()
    {
        // Create default application settings.
        aspectRatio = 1.3333F;
        lookupDir = "C:\\AppDirectory";
        autoSaveTime = 30;
        showStatusBar = false;

        if ( File.Exists(fileName) ) {
            BinaryReader binReader =
                new BinaryReader(File.Open(fileName, FileMode.Open));
            try {

				// If the file is not empty,
				// read the application settings.
				// Read 4 bytes into a buffer to
				// determine if the file is empty.
				ubyte[] testArray = new ubyte[3];
				int count = binReader.Read(testArray, 0, 3);
				if (count != 0)
				{
                    aspectRatio = binReader.ReadSingle();
                    lookupDir = binReader.ReadString();
                    autoSaveTime = binReader.ReadInt32();
                    showStatusBar = binReader.ReadBoolean();
                }
            }

            // If the end of the stream is reached before reading
            // the four data values, ignore the error and use the
            // default settings for the remaining values.
            catch(EndOfStreamException e) {
                Console.WriteLine("{0} caught and ignored. "
                    + "Using default values.", e.GetType().get_Name());
            }
            finally {
                binReader.Close();
            }
        }
    } //AppSettings

    // Create a file and store the application settings.
    public void Close()
    {
        BinaryWriter binWriter =
            new BinaryWriter(File.Open(fileName, FileMode.Create));
        try {
            binWriter.Write(aspectRatio);
            binWriter.Write(lookupDir);
            binWriter.Write(autoSaveTime);
            binWriter.Write(showStatusBar);
        }
        finally {
            if ( binWriter != null ) {
                binWriter= null;
            }
        }
    } //Close
} //AppSettings

System.Object
  System.IO.BinaryWriter

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0

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