.NET Framework Class Library
BinaryReader Class
Reads primitive data types as binary values in a specific encoding.
Namespace: System.IO
Assembly: mscorlib (in mscorlib.dll)
System.IO.BinaryReader
Assembly: mscorlib (in mscorlib.dll)
Syntax
Visual Basic (Declaration)
<ComVisibleAttribute(True)> _ Public Class BinaryReader Implements IDisposable
Visual Basic (Usage)
Dim instance As BinaryReader
C#
[ComVisibleAttribute(true)] public class BinaryReader : IDisposable
C++
[ComVisibleAttribute(true)] public ref class BinaryReader : IDisposable
J#
/** @attribute ComVisibleAttribute(true) */ public class BinaryReader implements IDisposable
JScript
ComVisibleAttribute(true) public class BinaryReader implements IDisposable
Remarks
The following table lists examples of other typical or related I/O tasks.
| To do this... | See the example in this topic... |
|---|---|
| Create a text file. | |
| Write to a text file. | |
| Read from a text file. | |
| Read from a binary file. | |
| Write to a binary file. |
Example
The following code example demonstrates how to store and retrieve application settings in a file.
Visual Basic
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. If binReader.PeekChar() <> -1 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
C#
using System; using System.IO; using System.Security.Permissions; class Test { static void Main() { // 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[4]{appSettings.AspectRatio.ToString(), appSettings.LookupDir, appSettings.AutoSaveTime.ToString(), appSettings.ShowStatusBar.ToString()}); // Change the settings. appSettings.AspectRatio = 1.250F; appSettings.LookupDir = @"C:\Temp"; appSettings.AutoSaveTime = 10; appSettings.ShowStatusBar = true; // Save the new settings. appSettings.Close(); } } // Store and retrieve application settings. class AppSettings { const string fileName = "AppSettings#@@#.dat"; float aspectRatio; string lookupDir; int autoSaveTime; bool showStatusBar; public float AspectRatio { get{ return aspectRatio; } set{ aspectRatio = value; } } public string LookupDir { get{ return lookupDir; } set{ lookupDir = value; } } public int AutoSaveTime { get{ return autoSaveTime; } set{ autoSaveTime = value; } } public bool ShowStatusBar { get{ return showStatusBar; } set{ showStatusBar = value; } } 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. if(binReader.PeekChar() != -1) { 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().Name); } finally { binReader.Close(); } } } // Create a file and store the application settings. public void Close() { using(BinaryWriter binWriter = new BinaryWriter(File.Open(fileName, FileMode.Create))) { binWriter.Write(aspectRatio); binWriter.Write(lookupDir); binWriter.Write(autoSaveTime); binWriter.Write(showStatusBar); } } }
C++
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. if ( binReader->PeekChar() != -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(); }
J#
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.
if ( binReader.PeekChar() !=-1 ) {
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
Inheritance Hierarchy
System.Object System.IO.BinaryReader
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.Platforms
Windows 98, Windows 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 .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
Version Information
.NET Framework
Supported in: 2.0, 1.1, 1.0.NET Compact Framework
Supported in: 2.0, 1.0See Also