StreamingContextとは? わかりやすく解説

StreamingContext コンストラクタ (StreamingContextStates)

コンテキストの状態を指定してStreamingContext クラス新しインスタンス初期化します。

名前空間: System.Runtime.Serialization
アセンブリ: mscorlib (mscorlib.dll 内)
構文構文

Public Sub New ( _
    state As StreamingContextStates _
)
Dim state As StreamingContextStates

Dim instance As New StreamingContext(state)
public StreamingContext (
    StreamingContextStates state
)
public:
StreamingContext (
    StreamingContextStates state
)
public StreamingContext (
    StreamingContextStates state
)
public function StreamingContext (
    state : StreamingContextStates
)

パラメータ

state

この StreamingContext の転送元のコンテキストまたは転送先のコンテキスト指定する StreamingContextStates 値のビットごとの組み合わせ

プラットフォームプラットフォーム
バージョン情報バージョン情報
参照参照
関連項目
StreamingContext 構造体
StreamingContext メンバ
System.Runtime.Serialization 名前空間
FlagsAttribute

StreamingContext コンストラクタ (StreamingContextStates, Object)

コンテキストの状態と追加情報指定してStreamingContext クラス新しインスタンス初期化します。

名前空間: System.Runtime.Serialization
アセンブリ: mscorlib (mscorlib.dll 内)
構文構文

Public Sub New ( _
    state As StreamingContextStates, _
    additional As Object _
)
Dim state As StreamingContextStates
Dim additional As Object

Dim instance As New StreamingContext(state,
 additional)
public StreamingContext (
    StreamingContextStates state,
    Object additional
)
public:
StreamingContext (
    StreamingContextStates state, 
    Object^ additional
)
public StreamingContext (
    StreamingContextStates state, 
    Object additional
)
public function StreamingContext (
    state : StreamingContextStates, 
    additional : Object
)

パラメータ

state

この StreamingContext の転送元のコンテキストまたは転送先のコンテキスト指定する StreamingContextStates 値のビットごとの組み合わせ

additional

StreamingContext関連付ける追加情報。この情報は、ISerializable を実装する任意のオブジェクトまたは任意のシリアル化サロゲート使用できます。ほとんどのユーザーは、このパラメータ設定する要はありません。

使用例使用例

state パラメータadditional パラメータ使用してStreamingContext クラスインスタンス作成する例を次に示します

Imports System
Imports System.Text
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization
Imports System.IO
Imports System.Security.Permissions


Class Program
    
    Shared Sub Main(ByVal
 args() As String) 
        Try
            SerializeAndDeserialize()
        Catch exc As System.Exception
            Console.WriteLine(exc.Message)
        Finally
            Console.WriteLine("Press <Enter> to exit....")
            Console.ReadLine()
        End Try
    
    End Sub 
    
    Shared Sub SerializeAndDeserialize() 
        Dim myObject As Object
 = DateTime.Now
        ' Create a StreamingContext that includes a
        ' a DateTime. 
        Dim sc As New StreamingContext(StreamingContextStates.CrossProcess,
 myObject)
        Dim bf As New BinaryFormatter(Nothing,
 sc)
        Dim ms As New MemoryStream(New
 Byte(2047) {})
        bf.Serialize(ms, New [MyClass]())
        ms.Seek(0, SeekOrigin.Begin)
        Dim f As [MyClass] = CType(bf.Deserialize(ms),
 [MyClass])
        Console.WriteLine(vbTab + " MinValue: {0} "
 + vbLf + vbTab + " MaxValue: {1}", f.MinValue, f.MaxValue)
        Console.WriteLine("StreamingContext.State: {0}",
 sc.State)
        
        Dim myDateTime As DateTime = CType(sc.Context,
 DateTime)
        Console.WriteLine("StreamingContext.Context: {0}",
 myDateTime.ToLongTimeString())
    
    End Sub 
End Class 

<Serializable(), SecurityPermission(SecurityAction.Demand, SerializationFormatter
 := True)>  _
Class [MyClass]
    Implements ISerializable
    Private minValue_value As Integer
    Private maxValue_value As Integer
    
    Public Sub New() 
        minValue_value = Integer.MinValue
        maxValue_value = Integer.MaxValue    
    End Sub     
    
    Public Property MinValue() As
 Integer 
        Get
            Return minValue_value
        End Get
        Set
            minValue_value = value
        End Set
    End Property 
    
    Public Property MaxValue() As
 Integer 
        Get
            Return maxValue_value
        End Get
        Set
            maxValue_value = value
        End Set
    End Property
     
    Sub GetObjectData(ByVal si As
 SerializationInfo, ByVal context As StreamingContext)
  Implements ISerializable.GetObjectData
        si.AddValue("minValue", minValue_value)
        si.AddValue("maxValue", maxValue_value)
    
    End Sub   
    
    Protected Sub New(ByVal
 si As SerializationInfo, ByVal context As
 StreamingContext) 
        minValue_value = Fix(si.GetValue("minValue",
 GetType(Integer)))
        maxValue_value = Fix(si.GetValue("maxValue",
 GetType(Integer)))
    End Sub 
End Class 
using System;
using System.Text;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;
using System.IO;
using System.Security.Permissions;

namespace StreamingContextExample
{
    class Program
    {
        static void Main(string[]
 args)
        {
            try
            {
                SerializeAndDeserialize();
            }
            catch (System.Exception exc)
            {
                Console.WriteLine(exc.Message);
            }
            finally
            {
                Console.WriteLine("Press <Enter> to exit....");
                Console.ReadLine();
            }
        }
        static void SerializeAndDeserialize()
        {
            object myObject = DateTime.Now;
            // Create a StreamingContext that includes a
            // a DateTime. 
            StreamingContext sc = new StreamingContext(
                StreamingContextStates.CrossProcess, myObject);
            BinaryFormatter bf = new BinaryFormatter(null,
 sc);
            MemoryStream ms = new MemoryStream(new
 byte[2048]);
            bf.Serialize(ms, new MyClass());
            ms.Seek(0, SeekOrigin.Begin);
            MyClass f = (MyClass)bf.Deserialize(ms);
            Console.WriteLine("\t MinValue: {0} \n\t MaxValue: {1}", 
                f.MinValue , f.MaxValue);
            Console.WriteLine("StreamingContext.State: {0}", 
                sc.State);

            DateTime myDateTime = (DateTime)sc.Context;
            Console.WriteLine("StreamingContext.Context: {0}",
                myDateTime.ToLongTimeString());
        }
    }

    [Serializable]
    [SecurityPermission(SecurityAction.Demand, SerializationFormatter = true)]
    class MyClass : ISerializable
    {
        private int minValue_value;
        private int maxValue_value;

        public MyClass()
        {
            minValue_value = int.MinValue;
            maxValue_value = int.MaxValue;
        }

        public int MinValue
        {
            get { return minValue_value; }
            set { minValue_value = value;}
        }

        public int MaxValue
        {
            get { return maxValue_value; }
            set { maxValue_value = value; }
        }

        void ISerializable.GetObjectData(SerializationInfo si,
 StreamingContext context)
        {
            si.AddValue("minValue", minValue_value);
            si.AddValue("maxValue", maxValue_value);
        }

        protected MyClass(SerializationInfo si, StreamingContext
 context)
        {
            minValue_value = (int)si.GetValue("minValue",
 typeof(int));
            maxValue_value = (int)si.GetValue("maxValue",
 typeof(int));            
        }
    }
}
プラットフォームプラットフォーム
バージョン情報バージョン情報
参照参照
関連項目
StreamingContext 構造体
StreamingContext メンバ
System.Runtime.Serialization 名前空間
FlagsAttribute
Equals

StreamingContext コンストラクタ

StreamingContext クラス新しインスタンス初期化します。
オーバーロードの一覧オーバーロードの一覧

名前 説明
StreamingContext (StreamingContextStates) コンテキストの状態を指定してStreamingContext クラス新しインスタンス初期化します。
StreamingContext (StreamingContextStates, Object) コンテキストの状態と追加情報指定してStreamingContext クラス新しインスタンス初期化します。
参照参照

関連項目

StreamingContext 構造体
StreamingContext メンバ
System.Runtime.Serialization 名前空間
FlagsAttribute

StreamingContext プロパティ


パブリック プロパティパブリック プロパティ

参照参照

関連項目

StreamingContext 構造体
System.Runtime.Serialization 名前空間
State

その他の技術情報

XML シリアル化および SOAP シリアル化

StreamingContext メソッド


StreamingContext メンバ


StreamingContext 構造体

指定したシリアル化ストリーム転送元と転送先を記述し呼び出し元によって定義され追加コンテキスト提供します

名前空間: System.Runtime.Serialization
アセンブリ: mscorlib (mscorlib.dll 内)
構文構文

<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Structure StreamingContext
Dim instance As StreamingContext
[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public struct StreamingContext
[SerializableAttribute] 
[ComVisibleAttribute(true)] 
public value class StreamingContext
/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
public final class StreamingContext extends
 ValueType
JScript では、構造体使用できますが、新規に宣言することはできません。
解説解説

フォーマッタ使用するビット転送元または転送先を示しますサロゲートを持つクラス、または ISerializable を実装するクラスは、ストリーム コンテキスト格納されている情報基づいてフィールドおよび値をシリアル化または無視できます。たとえば、State プロパティSystem.Runtime.Serialization.StreamingContextStates.CrossProcess設定されていても、ウィンドウ ハンドルは有効です。

使用例使用例

StreamingContext 構造体コード例次に示します

Imports System
Imports System.IO
Imports System.Collections
Imports System.Runtime.Serialization.Formatters.Binary
Imports System.Runtime.Serialization
Imports System.Runtime.InteropServices
Imports System.Security.Permissions

<Assembly: SecurityPermission( _
SecurityAction.RequestMinimum, Execution:=True)> 
' This class includes several Win32 interop definitions.
Friend Class Win32
    Public Shared ReadOnly
 InvalidHandleValue As New IntPtr(-1)
    Public Const FILE_MAP_WRITE As
 Int32 = 2
    Public Const PAGE_READWRITE As
 Int32 = &H4

    <DllImport("Kernel32")> _
    Public Shared Function
 CreateFileMapping(ByVal hFile As IntPtr,
 _
                                             ByVal pAttributes
 As IntPtr, _
                                             ByVal flProtect As
 Int32, _
                                             ByVal dwMaximumSizeHigh
 As Int32, _
                                             ByVal dwMaximumSizeLow
 As Int32, _
                                             ByVal pName As
 String) As IntPtr
    End Function

    <DllImport("Kernel32")> _
    Public Shared Function
 OpenFileMapping(ByVal dwDesiredAccess As
 Int32, _
                                           ByVal bInheritHandle
 As Boolean, _
                                           ByVal name As
 String) As IntPtr
    End Function

    <DllImport("Kernel32")> _
    Public Shared Function
 CloseHandle(ByVal handle As IntPtr) As
 Boolean
    End Function

    <DllImport("Kernel32")> _
    Public Shared Function
 MapViewOfFile(ByVal hFileMappingObject As
 IntPtr, _
                                         ByVal dwDesiredAccess
 As Int32, _
                                         ByVal dwFileOffsetHigh
 As Int32, _
                                         ByVal dwFileOffsetLow
 As Int32, _
                                         ByVal dwNumberOfBytesToMap
 As IntPtr) _
                                         As IntPtr
    End Function

    <DllImport("Kernel32")> _
    Public Shared Function
 UnmapViewOfFile(ByVal address As IntPtr)
 As Boolean
    End Function

    <DllImport("Kernel32")> _
    Public Shared Function
 DuplicateHandle(ByVal hSourceProcessHandle As
 IntPtr, _
                                           ByVal hSourceHandle
 As IntPtr, _
                                           ByVal hTargetProcessHandle
 As IntPtr, _
                                           ByRef lpTargetHandle
 As IntPtr, _
                                           ByVal dwDesiredAccess
 As Int32, _
                                           ByVal bInheritHandle
 As Boolean, _
                                           ByVal dwOptions As
 Int32) As Boolean
    End Function

    Public Const DUPLICATE_CLOSE_SOURCE As
 Int32 = &H1
    Public Const DUPLICATE_SAME_ACCESS As
 Int32 = &H2

    <DllImport("Kernel32")> Public
 Shared Function GetCurrentProcess() As
 IntPtr
    End Function
End Class


' This class wraps memory that can be simultaneously 
' shared by multiple AppDomains and Processes.
<Serializable()> Public NotInheritable
 Class SharedMemory
    Implements ISerializable
    Implements IDisposable

    ' The handle and string that identify 
    ' the Windows file-mapping object.
    Private m_hFileMap As IntPtr = IntPtr.Zero
    Private m_name As String

    ' The address of the memory-mapped file-mapping object.
    Private m_address As IntPtr
    <SecurityPermissionAttribute(SecurityAction.LinkDemand, _
    Flags:=SecurityPermissionFlag.UnmanagedCode)> _
    Public Function GetByte(ByVal
 offset As Int32) As Byte
        Dim b(0) As Byte
        Marshal.Copy(New IntPtr(m_address.ToInt64() + offset),
 b, 0, 1)
        Return b(0)
    End Function

    <SecurityPermissionAttribute(SecurityAction.LinkDemand, _
    Flags:=SecurityPermissionFlag.UnmanagedCode)> _
    Public Sub SetByte(ByVal
 offset As Int32, ByVal value As
 Byte)
        Dim b(0) As Byte
        b(0) = value
        Marshal.Copy(b, 0, New IntPtr(m_address.ToInt64() + offset),
 1)
    End Sub


    ' The constructors.
    Public Sub New(ByVal
 size As Int32)
        Me.New(size, Nothing)
    End Sub

    Public Sub New(ByVal
 size As Int32, ByVal name As
 String)
        m_hFileMap = Win32.CreateFileMapping(Win32.InvalidHandleValue, _
           IntPtr.Zero, Win32.PAGE_READWRITE, 0, size, name)
        If (m_hFileMap.Equals(IntPtr.Zero)) Then
 _
           Throw New Exception("Could
 not create memory-mapped file.")
        m_name = name
        m_address = Win32.MapViewOfFile(m_hFileMap, _
           Win32.FILE_MAP_WRITE, 0, 0, IntPtr.Zero)
    End Sub


    ' The cleanup methods.
    Public Sub Dispose() Implements
 IDisposable.Dispose
        GC.SuppressFinalize(Me)
        Dispose(True)
    End Sub

    Private Sub Dispose(ByVal
 disposing As Boolean)
        Win32.UnmapViewOfFile(m_address)
        Win32.CloseHandle(m_hFileMap)
        m_address = IntPtr.Zero
        m_hFileMap = IntPtr.Zero
    End Sub

    Protected Overrides Sub
 Finalize()
        Dispose(False)
    End Sub


    ' Private helper methods.
    Private Shared Function
 AllFlagsSet(ByVal flags As Int32, _
                                        ByVal flagsToTest As
 Int32) As Boolean
        Return (flags And flagsToTest) = flagsToTest
    End Function

    Private Shared Function
 AnyFlagsSet(ByVal flags As Int32, _
                                        ByVal flagsToTest As
 Int32) As Boolean
        Return (flags And flagsToTest) <>
 0
    End Function


    ' The security attribute demands that code that calls  
    ' this method have permission to perform serialization.
    <SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter:=True)>
 _
    Sub GetObjectData(ByVal info As
 SerializationInfo, _
                      ByVal context As StreamingContext)
 _
                      Implements ISerializable.GetObjectData
        ' The context's State member indicates where the object will
 be deserialized.

        ' A SharedMemory object cannot be serialized 
        ' to any of the following destinations.
        Const InvalidDestinations As StreamingContextStates
 = _
           StreamingContextStates.CrossMachine Or _
           StreamingContextStates.File Or _
           StreamingContextStates.Other Or _
           StreamingContextStates.Persistence Or _
           StreamingContextStates.Remoting
        If AnyFlagsSet(CType(context.State, Int32), _
                       CType(InvalidDestinations, Int32)) Then
            Throw New SerializationException("The
 SharedMemory object " & _
               "cannot be serialized to any of the following streaming
 contexts: " _
               & InvalidDestinations)
        End If

        Const DeserializableByHandle As StreamingContextStates
 = _
                 StreamingContextStates.Clone Or _
                 StreamingContextStates.CrossAppDomain

        If AnyFlagsSet(CType(context.State, Int32), _
              CType(DeserializableByHandle, Int32)) Then
            info.AddValue("hFileMap", m_hFileMap)
        End If

        Const DeserializableByName As StreamingContextStates
 = _
                 StreamingContextStates.CrossProcess   ' The same computer.
        If AnyFlagsSet(CType(context.State, Int32), CType(DeserializableByName,
 _
                       Int32)) Then
            If m_name = Nothing Then
                Throw New SerializationException("The
 SharedMemory object " & _
                   "cannot be serialized CrossProcess because
 it was not constructed " & _
                   "with a String name.")
            End If
            info.AddValue("name", m_name)
        End If
    End Sub

    Private Sub New(ByVal
 info As SerializationInfo, ByVal context
 As StreamingContext)
        ' The context's State member indicates where the object was
 serialized from.

        Const InvalidSources As StreamingContextStates
 = _
                 StreamingContextStates.CrossMachine Or _
                 StreamingContextStates.File Or _
                 StreamingContextStates.Other Or _
                 StreamingContextStates.Persistence Or _
                 StreamingContextStates.Remoting

        If AnyFlagsSet(CType(context.State, Int32), CType(InvalidSources,
 Int32)) Then
            Throw New SerializationException("The
 SharedMemory object " & _
               "cannot be deserialized from any of the following
 stream contexts: " & _
               InvalidSources)
        End If

        Const SerializedByHandle As StreamingContextStates
 = _
                 StreamingContextStates.Clone Or _
                 StreamingContextStates.CrossAppDomain ' The same process.
        If AnyFlagsSet(CType(context.State, Int32), _
              CType(SerializedByHandle, Int32)) Then
            Try
                Win32.DuplicateHandle(Win32.GetCurrentProcess(), _
                   CType(info.GetValue("hFileMap",
 GetType(IntPtr)), IntPtr), _
                      Win32.GetCurrentProcess(), m_hFileMap, 0, False,
 _
                      Win32.DUPLICATE_SAME_ACCESS)
            Catch e As SerializationException
                Throw New SerializationException("A
 SharedMemory was not " & _
                   "serialized using any of the following streaming
 contexts: " & _
                   SerializedByHandle)
            End Try
        End If

        Const SerializedByName As StreamingContextStates
 = _
                 StreamingContextStates.CrossProcess   ' The same computer.
        If AnyFlagsSet(CType(context.State, Int32), _
                       CType(SerializedByName, Int32)) Then
            Try
                m_name = info.GetString("name")
            Catch e As SerializationException
                Throw New SerializationException("A
 SharedMemory object " & _
                   "was not serialized using any of the following
 streaming contexts: " & _
                   SerializedByName)
            End Try
            m_hFileMap = Win32.OpenFileMapping(Win32.FILE_MAP_WRITE, False,
 m_name)
        End If
        If Not m_hFileMap.Equals(IntPtr.Zero)
 Then
            m_address = Win32.MapViewOfFile(m_hFileMap, _
               Win32.FILE_MAP_WRITE, 0, 0, IntPtr.Zero)
        Else
            Throw New SerializationException("A
 SharedMemory object " & _
               "could not be deserialized.")
        End If
    End Sub
End Class

Class App
    <STAThread()> Shared Sub Main()
        Serialize()
        Console.WriteLine()
        Deserialize()
    End Sub

    Shared Sub Serialize()
        ' Create a hashtable of values that will eventually be serialized.
        Dim sm As New SharedMemory(1024,
 "MyMemory")
        Dim x As Int32
        For x = 0 To 99
            sm.SetByte(x, x)
        Next

        Dim b(9) As Byte
        For x = 0 To b.Length - 1
            b(x) = sm.GetByte(x)
        Next
        Console.WriteLine(BitConverter.ToString(b))

        ' To serialize the hashtable (and its key/value pairs), you
 must first 
        ' open a stream for writing. Use a file stream here.
        Dim fs As New FileStream("DataFile.dat",
 FileMode.Create)

        ' Construct a BinaryFormatter telling it where 
        ' the objects will be serialized to.
        Dim formatter As New
 BinaryFormatter(Nothing, _
           New StreamingContext(StreamingContextStates.CrossAppDomain))
        Try
            formatter.Serialize(fs, sm)
        Catch e As SerializationException
            Console.WriteLine("Failed to serialize. Reason: "
 + e.Message)
            Throw
        Finally
            fs.Close()
        End Try
    End Sub

    Shared Sub Deserialize()
        ' Declare the hashtable reference.
        Dim sm As SharedMemory = Nothing

        ' Open the file containing the data that you want to deserialize.
        Dim fs As New FileStream("DataFile.dat",
 FileMode.Open)
        Try
            Dim Formatter As New
 BinaryFormatter(Nothing, _
               New StreamingContext(StreamingContextStates.CrossAppDomain))

            ' Deserialize the SharedMemory object from the file and
 
            ' assign the reference to the local variable.
            sm = DirectCast(Formatter.Deserialize(fs), SharedMemory)
        Catch e As SerializationException
            Console.WriteLine("Failed to deserialize. Reason:
 " & e.Message)
        Finally
            fs.Close()
        End Try

        ' To prove that the SharedMemory object deserialized correctly,
 
        ' display some of its bytes to the console.
        Dim b(9) As Byte
        Dim x As Int32
        For x = 0 To b.Length - 1
            b(x) = sm.GetByte(x)
        Next
        Console.WriteLine(BitConverter.ToString(b))
    End Sub
End Class
// Note: You must compile this file using the C# /unsafe switch.
using System;
using System.IO;
using System.Collections;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;
using System.Runtime.InteropServices;
using System.Security.Permissions;

[assembly: SecurityPermission(
SecurityAction.RequestMinimum, Execution = true)]
// This class includes several Win32 interop definitions.
internal class Win32
{
    public static readonly IntPtr InvalidHandleValue
 = new IntPtr(-1);
    public const UInt32 FILE_MAP_WRITE = 2;
    public const UInt32 PAGE_READWRITE = 0x04;

    [DllImport("Kernel32")]
    public static extern IntPtr CreateFileMapping(IntPtr
 hFile,
        IntPtr pAttributes, UInt32 flProtect,
        UInt32 dwMaximumSizeHigh, UInt32 dwMaximumSizeLow, String pName);

    [DllImport("Kernel32")]
    public static extern IntPtr OpenFileMapping(UInt32
 dwDesiredAccess,
        Boolean bInheritHandle, String name);

    [DllImport("Kernel32")]
    public static extern Boolean CloseHandle(IntPtr
 handle);

    [DllImport("Kernel32")]
    public static extern IntPtr MapViewOfFile(IntPtr
 hFileMappingObject,
        UInt32 dwDesiredAccess,
        UInt32 dwFileOffsetHigh, UInt32 dwFileOffsetLow,
        IntPtr dwNumberOfBytesToMap);

    [DllImport("Kernel32")]
    public static extern Boolean UnmapViewOfFile(IntPtr
 address);

    [DllImport("Kernel32")]
    public static extern Boolean DuplicateHandle(IntPtr
 hSourceProcessHandle,
        IntPtr hSourceHandle,
        IntPtr hTargetProcessHandle, ref IntPtr lpTargetHandle,
        UInt32 dwDesiredAccess, Boolean bInheritHandle, UInt32 dwOptions);
    public const UInt32 DUPLICATE_CLOSE_SOURCE
 = 0x00000001;
    public const UInt32 DUPLICATE_SAME_ACCESS
 = 0x00000002;

    [DllImport("Kernel32")]
    public static extern IntPtr GetCurrentProcess();
}


// This class wraps memory that can be simultaneously 
// shared by multiple AppDomains and Processes.
[Serializable]
public sealed class SharedMemory : ISerializable,
 IDisposable
{
    // The handle and string that identify 
    // the Windows file-mapping object.
    private IntPtr m_hFileMap = IntPtr.Zero;
    private String m_name;

    // The address of the memory-mapped file-mapping object.
    private IntPtr m_address;

    public unsafe Byte* Address
    {
        get { return (Byte*)m_address; }
    }

    // The constructors.
    public SharedMemory(Int32 size) : this(size,
 null) { }

    public SharedMemory(Int32 size, String name)
    {
        m_hFileMap = Win32.CreateFileMapping(Win32.InvalidHandleValue,
            IntPtr.Zero, Win32.PAGE_READWRITE,
            0, unchecked((UInt32)size), name);
        if (m_hFileMap == IntPtr.Zero)
            throw new Exception("Could not create memory-mapped
 file.");
        m_name = name;
        m_address = Win32.MapViewOfFile(m_hFileMap, Win32.FILE_MAP_WRITE,
            0, 0, IntPtr.Zero);
    }

    // The cleanup methods.
    public void Dispose()
    {
        GC.SuppressFinalize(this);
        Dispose(true);
    }

    private void Dispose(Boolean disposing)
    {
        Win32.UnmapViewOfFile(m_address);
        Win32.CloseHandle(m_hFileMap);
        m_address = IntPtr.Zero;
        m_hFileMap = IntPtr.Zero;
    }

    ~SharedMemory()
    {
        Dispose(false);
    }

    // Private helper methods.
    private static Boolean AllFlagsSet(Int32
 flags, Int32 flagsToTest)
    {
        return (flags & flagsToTest) == flagsToTest;
    }

    private static Boolean AnyFlagsSet(Int32
 flags, Int32 flagsToTest)
    {
        return (flags & flagsToTest) != 0;
    }


    // The security attribute demands that code that calls  
    // this method have permission to perform serialization.
    [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter =
 true)]
    void ISerializable.GetObjectData(SerializationInfo info, StreamingContext
 context)
    {
        // The context's State member indicates
        // where the object will be deserialized.

        // A SharedMemory object cannot be serialized 
        // to any of the following destinations.
        const StreamingContextStates InvalidDestinations =
                  StreamingContextStates.CrossMachine |
                  StreamingContextStates.File |
                  StreamingContextStates.Other |
                  StreamingContextStates.Persistence |
                  StreamingContextStates.Remoting;
        if (AnyFlagsSet((Int32)context.State, (Int32)InvalidDestinations))
            throw new SerializationException("The SharedMemory
 object " +
                "cannot be serialized to any of the following streaming contexts:
 " +
                InvalidDestinations);

        const StreamingContextStates DeserializableByHandle =
                  StreamingContextStates.Clone |
            // The same process.
                  StreamingContextStates.CrossAppDomain;
        if (AnyFlagsSet((Int32)context.State, (Int32)DeserializableByHandle))
            info.AddValue("hFileMap", m_hFileMap);

        const StreamingContextStates DeserializableByName =
            // The same computer.
                  StreamingContextStates.CrossProcess;
        if (AnyFlagsSet((Int32)context.State, (Int32)DeserializableByName))
        {
            if (m_name == null)
                throw new SerializationException("The SharedMemory
 object " +
                    "cannot be serialized CrossProcess because it was not constructed
 " +
                    "with a String name.");
            info.AddValue("name", m_name);
        }
    }


    // The security attribute demands that code that calls  
    // this method have permission to perform serialization.
    [SecurityPermissionAttribute(SecurityAction.Demand, SerializationFormatter =
 true)]
    private SharedMemory(SerializationInfo info, StreamingContext
 context)
    {
        // The context's State member indicates 
        // where the object was serialized from.

        const StreamingContextStates InvalidSources =
                  StreamingContextStates.CrossMachine |
                  StreamingContextStates.File |
                  StreamingContextStates.Other |
                  StreamingContextStates.Persistence |
                  StreamingContextStates.Remoting;
        if (AnyFlagsSet((Int32)context.State, (Int32)InvalidSources))
            throw new SerializationException("The SharedMemory
 object " +
                "cannot be deserialized from any of the following stream contexts:
 " +
                InvalidSources);

        const StreamingContextStates SerializedByHandle =
                  StreamingContextStates.Clone |
            // The same process.
                  StreamingContextStates.CrossAppDomain;
        if (AnyFlagsSet((Int32)context.State, (Int32)SerializedByHandle))
        {
            try
            {
                Win32.DuplicateHandle(Win32.GetCurrentProcess(),
                    (IntPtr)info.GetValue("hFileMap", typeof(IntPtr)),
                    Win32.GetCurrentProcess(), ref m_hFileMap, 0, false
,
                    Win32.DUPLICATE_SAME_ACCESS);
            }
            catch (SerializationException)
            {
                throw new SerializationException("A SharedMemory
 was not serialized " +
                    "using any of the following streaming
 contexts: " +
                    SerializedByHandle);
            }
        }

        const StreamingContextStates SerializedByName =
            // The same computer.
                  StreamingContextStates.CrossProcess;
        if (AnyFlagsSet((Int32)context.State, (Int32)SerializedByName))
        {
            try
            {
                m_name = info.GetString("name");
            }
            catch (SerializationException)
            {
                throw new SerializationException("A SharedMemory
 object was not " +
                    "serialized using any of the following
 streaming contexts: " +
                    SerializedByName);
            }
            m_hFileMap = Win32.OpenFileMapping(Win32.FILE_MAP_WRITE, false,
 m_name);
        }
        if (m_hFileMap != IntPtr.Zero)
        {
            m_address = Win32.MapViewOfFile(m_hFileMap, Win32.FILE_MAP_WRITE,
                0, 0, IntPtr.Zero);
        }
        else
        {
            throw new SerializationException("A SharedMemory
 object could not " +
                "be deserialized.");
        }
    }
}


class App
{
    [STAThread]
    static void Main(string[]
 args)
    {
        Serialize();
        Console.WriteLine();
        Deserialize();
    }

    unsafe static void Serialize()
    {
        // Create a hashtable of values that will eventually be serialized.
        SharedMemory sm = new SharedMemory(1024, "JeffMemory");
        for (Int32 x = 0; x < 100; x++)
            *(sm.Address + x) = (Byte)x;

        Byte[] b = new Byte[10];
        for (Int32 x = 0; x < b.Length; x++) b[x] = *(sm.Address
 + x);
        Console.WriteLine(BitConverter.ToString(b));

        // To serialize the SharedMemory object, 
        // you must first open a stream for writing. 
        // Use a file stream here.
        FileStream fs = new FileStream("DataFile.dat",
 FileMode.Create);

        // Construct a BinaryFormatter and tell it where 
        // the objects will be serialized to.
        BinaryFormatter formatter = new BinaryFormatter(null
,
            new StreamingContext(StreamingContextStates.CrossAppDomain));
        try
        {
            formatter.Serialize(fs, sm);
        }
        catch (SerializationException e)
        {
            Console.WriteLine("Failed to serialize. Reason: " + e.Message);
            throw;
        }
        finally
        {
            fs.Close();
        }
    }


    unsafe static void Deserialize()
    {
        // Declare a SharedMemory reference.
        SharedMemory sm = null;

        // Open the file containing the data that you want to deserialize.
        FileStream fs = new FileStream("DataFile.dat",
 FileMode.Open);
        try
        {
            BinaryFormatter formatter = new BinaryFormatter(null
,
                new StreamingContext(StreamingContextStates.CrossAppDomain));

            // Deserialize the SharedMemory object from the file and
 
            // assign the reference to the local variable.
            sm = (SharedMemory)formatter.Deserialize(fs);
        }
        catch (SerializationException e)
        {
            Console.WriteLine("Failed to deserialize. Reason: " + e.Message);
            throw;
        }
        finally
        {
            fs.Close();
        }

        // To prove that the SharedMemory object deserialized correctly,
 
        // display some of its bytes to the console.
        Byte[] b = new Byte[10];
        for (Int32 x = 0; x < b.Length; x++) b[x] = *(sm.Address
 + x);
        Console.WriteLine(BitConverter.ToString(b));
    }
}
スレッド セーフスレッド セーフ
この型の public static (Visual Basic では Shared) メンバはすべて、スレッド セーフです。インスタンス メンバ場合は、スレッド セーフであるとは限りません。
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