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BinaryReader Class

Reads primitive data types as binary values in a specific encoding.

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

'Declaration
<ComVisibleAttribute(True)> _
Public Class BinaryReader
	Implements IDisposable
'Usage
Dim instance As BinaryReader

/** @attribute ComVisibleAttribute(true) */ 
public class BinaryReader implements IDisposable
ComVisibleAttribute(true) 
public class BinaryReader implements IDisposable
Not applicable.

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.

Imports Microsoft.VisualBasic
Imports System
Imports System.IO
Imports System.Security.Permissions

Public Class Test

    Shared Sub Main()

        ' Load application settings.
        Dim appSettings As New AppSettings()
        Console.WriteLine("App settings." & vbcrLf & "Aspect " & _
            "Ratio: {0}, Lookup directory: {1}," & vbcrLf & "Auto " & _
            "save time: {2} minutes, Show status bar: {3}" & vbCrLf, _
            New Object(3){appSettings.AspectRatio.ToString(), _
            appSettings.LookupDir, _
            appSettings.AutoSaveTime.ToString(), _
            appSettings.ShowStatusBar.ToString()})

        ' Change the settings.
        appSettings.AspectRatio   = 1.250
        appSettings.LookupDir     = "C:\Temp"
        appSettings.AutoSaveTime  = 10
        appSettings.ShowStatusBar = True

        ' Save the new settings.
        appSettings.Close()
   
    End Sub
End Class

' Store and retrieve application settings.
Public Class AppSettings

    Const fileName As String = "AppSettings#@@#.dat"
    Dim aspRatio As Single
    Dim lkupDir As String
    Dim saveTime As Integer
    Dim statusBar As Boolean

    Property AspectRatio As Single
        Get
            Return aspRatio
        End Get
        Set
            aspRatio = Value
        End Set
    End Property
   
    Property LookupDir As String
        Get
            Return lkupDir
        End Get
        Set
            lkupDir = Value
        End Set
    End Property
   
    Property AutoSaveTime As Integer
        Get
            Return saveTime
        End Get
        Set
            saveTime = Value
        End Set
    End Property
   
    Property ShowStatusBar As Boolean
        Get
            Return statusBar
        End Get
        Set
            statusBar = Value
        End Set
    End Property

    Sub New()

        ' Create default application settings.
        aspRatio   = 1.3333
        lkupDir     = "C:\AppDirectory"
        saveTime  = 30
        statusBar = False

        If File.Exists(fileName) Then
            Dim binReader As 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.
                Dim testArray As Byte() = {0,0,0,0}
                Dim count As Integer = binReader.Read(testArray, 0, 3)

                If count <> 0 Then
                    aspRatio   = binReader.ReadSingle()
                    lkupDir     = binReader.ReadString()
                    saveTime  = binReader.ReadInt32()
                    statusBar = binReader.ReadBoolean()
                    Return
                End If

            ' 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 ex As EndOfStreamException
                Console.WriteLine("{0} caught and ignored. " & _ 
                    "Using default values.", ex.GetType().Name)
            Finally
                binReader.Close()
            End Try
        End If

    End Sub

    ' Create a file and store the application settings.
    Sub Close()
        Dim binWriter As New BinaryWriter( _
            File.Open(fileName, FileMode.Create))
        Try
            binWriter.Write(aspRatio)
            binWriter.Write(lkupDir)
            binWriter.Write(saveTime)
            binWriter.Write(statusBar)
        Finally
            binWriter.Close()
        End Try
    End Sub

End Class

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.BinaryReader

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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