BinaryReader クラス

[アーティクル]
03/28/2008

プリミティブデータ型を特定のエンコーディングのバイナリ値として読み取ります。

この型のすべてのメンバの一覧については、BinaryReader メンバを参照してください。

System.Object
System.IO.BinaryReader

Public Class BinaryReader
   Implements IDisposable
[C#]
public class BinaryReader : IDisposable
[C++]
public __gc class BinaryReader : public IDisposable
[JScript]
public class BinaryReader implements IDisposable

スレッドセーフ

この型の public static (Visual Basicでは Shared) のすべてのメンバは、マルチスレッド操作で安全に使用できます。インスタンスのメンバの場合は、スレッドセーフであるとは限りません。

解説

その他の一般的な I/O タスクまたは関連する I/O タスクの例を次の表に示します。

実行するタスク	参考例があるトピック
テキストファイルを作成する。	ファイルへのテキストの書き込み
テキストファイルに書き込む。	ファイルへのテキストの書き込み
テキストファイルから読み取る。	ファイルからのテキストの読み取り
バイナリファイルから読み取る。	新しく作成したデータファイルの読み取りと書き込み
バイナリファイルに書き込む。	新しく作成したデータファイルの読み取りと書き込み

使用例

[Visual Basic, C#, C++] アプリケーションの設定をファイルに保存する方法とファイルから取得する方法の例を次に示します。

 
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 <mscorlib.dll>
using namespace System;
using namespace System::IO;
using namespace System::Security::Permissions;

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

public:
    __property float get_AspectRatio()
    { return aspectRatio; }
    __property void set_AspectRatio(float value)
    { aspectRatio = value; }

    __property String* get_LookupDir()
    { return lookupDir; }
    __property void set_LookupDir(String* value)
    { lookupDir = value; }

    __property int get_AutoSaveTime()
     { return autoSaveTime; }
    __property void set_AutoSaveTime(int value)
    { autoSaveTime = value; }

    __property Boolean get_ShowStatusBar()
    { return showStatusBar; }
    __property void set_ShowStatusBar(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 = 
                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();
                    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(S"{0} caught and ignored. "
                    S"Using default values.", e->GetType()->Name);
            }
            __finally
            {
                binReader->Close();
            }
        }
    }

    // Create a file and store the application settings.
    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
        {
            binWriter->Close();
        }
    }
};

void main()
{
    // Load application settings.
    AppSettings* appSettings = new AppSettings();
    Object* someObject[] = {appSettings->AspectRatio.ToString(), 
        appSettings->LookupDir, appSettings->AutoSaveTime.ToString(), 
        appSettings->ShowStatusBar.ToString()};
    Console::WriteLine(S"App settings.\nAspect Ratio: {0}, " 
        S"Lookup directory: {1},\nAuto save time: {2} minutes, " 
        S"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();
}

[JScript] JScript のサンプルはありません。Visual Basic、C#、および C++ のサンプルを表示するには、このページの左上隅にある言語のフィルタボタンをクリックします。

必要条件

名前空間: System.IO

プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET

アセンブリ: Mscorlib (Mscorlib.dll 内)

参照

BinaryReader クラス

スレッドセーフ

解説

使用例

必要条件

参照

その他のリソース