WaitHandle クラス

.NET Framework クラス ライブラリ リファレンス

WaitHandle クラス

共有リソースへの排他アクセスの待機に使用するオペレーティング システム固有のオブジェクトをカプセル化します。

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

Visual Basic (宣言)

<ComVisibleAttribute(True)> _
Public MustInherit Class
 WaitHandle
    Inherits MarshalByRefObject
    Implements IDisposable

Visual Basic (使用法)

Dim instance As WaitHandle

C#

[ComVisibleAttribute(true)] 
public abstract class WaitHandle : MarshalByRefObject,
 IDisposable

C++

[ComVisibleAttribute(true)] 
public ref class WaitHandle abstract : public
 MarshalByRefObject, IDisposable

J#

/** @attribute ComVisibleAttribute(true) */ 
public abstract class WaitHandle extends MarshalByRefObject
 implements IDisposable

JScript

ComVisibleAttribute(true) 
public abstract class WaitHandle extends
 MarshalByRefObject implements IDisposable

解説

このクラスは、通常、同期オブジェクトの基本クラスとして使用されます。WaitHandle から派生したクラスは、共有リソースへのアクセスの取得または解放を示すシグナル通知機構を定義しますが、共有リソースへのアクセスを待機している間にブロックするには、継承した WaitHandle メソッドを使用します。

このクラスの静的メソッドを使用して、1 つ以上の同期オブジェクトがシグナルを受信するまでスレッドをブロックします。

使用例

2 つのスレッドがバックグラウンド タスクを実行し、その間にメイン スレッドが WaitHandle クラスの WaitAny 静的メソッドおよび WaitAll 静的メソッドを使用してタスクの完了を待機できるようにするコード例を次に示します。

Visual Basic

Imports System
Imports System.Threading

NotInheritable Public Class
 App
    ' Define an array with two AutoResetEvent WaitHandles.
    Private Shared waitHandles() As
 WaitHandle = _
        {New AutoResetEvent(False), New AutoResetEvent(False)}
    
    ' Define a random number generator for testing.
    Private Shared r As
 New Random()
    
    <MTAThreadAttribute> _
    Public Shared Sub Main()
 
        ' Queue two tasks on two different threads; 
        ' wait until all tasks are completed.
        Dim dt As DateTime = DateTime.Now
        Console.WriteLine("Main thread is waiting for BOTH tasks
 to complete.")
        ThreadPool.QueueUserWorkItem(AddressOf DoTask, waitHandles(0))
        ThreadPool.QueueUserWorkItem(AddressOf DoTask, waitHandles(1))
        WaitHandle.WaitAll(waitHandles)
        ' The time shown below should match the longest task.
        Console.WriteLine("Both tasks are completed (time waited={0})",
 _
            (DateTime.Now - dt).TotalMilliseconds)
        
        ' Queue up two tasks on two different threads; 
        ' wait until any tasks are completed.
        dt = DateTime.Now
        Console.WriteLine()
        Console.WriteLine("The main thread is waiting for either
 task to complete.")
        ThreadPool.QueueUserWorkItem(AddressOf DoTask, waitHandles(0))
        ThreadPool.QueueUserWorkItem(AddressOf DoTask, waitHandles(1))
        Dim index As Integer
 = WaitHandle.WaitAny(waitHandles)
        ' The time shown below should match the shortest task.
        Console.WriteLine("Task {0} finished first (time waited={1}).",
 _
            index + 1,(DateTime.Now - dt).TotalMilliseconds)
    
    End Sub 'Main
    
    Shared Sub DoTask(ByVal
 state As [Object]) 
        Dim are As AutoResetEvent = CType(state,
 AutoResetEvent)
        Dim time As Integer
 = 1000 * r.Next(2, 10)
        Console.WriteLine("Performing a task for {0} milliseconds.",
 time)
        Thread.Sleep(time)
        are.Set()
    
    End Sub 'DoTask
End Class 'App

' This code produces output similar to the following:
'
'  Main thread is waiting for BOTH tasks to complete.
'  Performing a task for 7000 milliseconds.
'  Performing a task for 4000 milliseconds.
'  Both tasks are completed (time waited=7064.8052)
' 
'  The main thread is waiting for either task to complete.
'  Performing a task for 2000 milliseconds.
'  Performing a task for 2000 milliseconds.
'  Task 1 finished first (time waited=2000.6528).

C#

using System;
using System.Threading;

public sealed class App 
{
    // Define an array with two AutoResetEvent WaitHandles.
    static WaitHandle[] waitHandles = new WaitHandle[]
 
    {
        new AutoResetEvent(false),
        new AutoResetEvent(false)
    };

    // Define a random number generator for testing.
    static Random r = new Random();

    static void Main() 
    {
        // Queue up two tasks on two different threads; 
        // wait until all tasks are completed.
        DateTime dt = DateTime.Now;
        Console.WriteLine("Main thread is waiting for BOTH
 tasks to complete.");
        ThreadPool.QueueUserWorkItem(new WaitCallback(DoTask),
 waitHandles[0]);
        ThreadPool.QueueUserWorkItem(new WaitCallback(DoTask),
 waitHandles[1]);
        WaitHandle.WaitAll(waitHandles);
        // The time shown below should match the longest task.
        Console.WriteLine("Both tasks are completed (time waited={0})",
 
            (DateTime.Now - dt).TotalMilliseconds);

        // Queue up two tasks on two different threads; 
        // wait until any tasks are completed.
        dt = DateTime.Now;
        Console.WriteLine();
        Console.WriteLine("The main thread is waiting for
 either task to complete.");
        ThreadPool.QueueUserWorkItem(new WaitCallback(DoTask),
 waitHandles[0]);
        ThreadPool.QueueUserWorkItem(new WaitCallback(DoTask),
 waitHandles[1]);
        int index = WaitHandle.WaitAny(waitHandles);
        // The time shown below should match the shortest task.
        Console.WriteLine("Task {0} finished first (time waited={1})."
,
            index + 1, (DateTime.Now - dt).TotalMilliseconds);
    }

    static void DoTask(Object state) 
    {
        AutoResetEvent are = (AutoResetEvent) state;
        int time = 1000 * r.Next(2, 10);
        Console.WriteLine("Performing a task for {0} milliseconds.",
 time);
        Thread.Sleep(time);
        are.Set();
    }
}

// This code produces output similar to the following:
//
//  Main thread is waiting for BOTH tasks to complete.
//  Performing a task for 7000 milliseconds.
//  Performing a task for 4000 milliseconds.
//  Both tasks are completed (time waited=7064.8052)
// 
//  The main thread is waiting for either task to complete.
//  Performing a task for 2000 milliseconds.
//  Performing a task for 2000 milliseconds.
//  Task 1 finished first (time waited=2000.6528).

C++

using namespace System;
using namespace System::Threading;

public ref class WaitHandleExample
{
    // Define a random number generator for testing.
private:
    static Random^ random = gcnew Random();
public:
    static void DoTask(Object^ state)
    {
        AutoResetEvent^ autoReset = (AutoResetEvent^) state;
        int time = 1000 * random->Next(2, 10);
        Console::WriteLine("Performing a task for {0} milliseconds.",
 time);
        Thread::Sleep(time);
        autoReset->Set();
    }
};

int main()
{
    // Define an array with two AutoResetEvent WaitHandles.
    array<WaitHandle^>^ handles = gcnew array<WaitHandle^> {
        gcnew AutoResetEvent(false), gcnew AutoResetEvent(false)};

    // Queue up two tasks on two different threads;
    // wait until all tasks are completed.
    DateTime timeInstance = DateTime::Now;
    Console::WriteLine("Main thread is waiting for BOTH tasks
 to " +
        "complete.");
    ThreadPool::QueueUserWorkItem(
        gcnew WaitCallback(WaitHandleExample::DoTask), handles[0]);
    ThreadPool::QueueUserWorkItem(
        gcnew WaitCallback(WaitHandleExample::DoTask), handles[1]);
    WaitHandle::WaitAll(handles);
    // The time shown below should match the longest task.
    Console::WriteLine("Both tasks are completed (time waited={0})",
        (DateTime::Now - timeInstance).TotalMilliseconds);

    // Queue up two tasks on two different threads;
    // wait until any tasks are completed.
    timeInstance = DateTime::Now;
    Console::WriteLine();
    Console::WriteLine("The main thread is waiting for either
 task to " +
        "complete.");
    ThreadPool::QueueUserWorkItem(
        gcnew WaitCallback(WaitHandleExample::DoTask), handles[0]);
    ThreadPool::QueueUserWorkItem(
        gcnew WaitCallback(WaitHandleExample::DoTask), handles[1]);
    int index = WaitHandle::WaitAny(handles);
    // The time shown below should match the shortest task.
    Console::WriteLine("Task {0} finished first (time waited={1}).",
        index + 1, (DateTime::Now - timeInstance).TotalMilliseconds);
}

// This code produces the following sample output.
//
// Main thread is waiting for BOTH tasks to complete.
// Performing a task for 7000 milliseconds.
// Performing a task for 4000 milliseconds.
// Both tasks are completed (time waited=7064.8052)

// The main thread is waiting for either task to complete.
// Performing a task for 2000 milliseconds.
// Performing a task for 2000 milliseconds.
// Task 1 finished first (time waited=2000.6528).

継承階層

System.Object
   System.MarshalByRefObject
    System.Threading.WaitHandle
       System.Threading.EventWaitHandle
       System.Threading.Mutex
       System.Threading.Semaphore

スレッド セーフ

この型は、スレッド セーフです。

プラットフォーム

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

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
WaitHandle メンバ
System.Threading 名前空間
その他の技術情報
待機ハンドル