RegisteredWaitHandle.Unregister(WaitHandle) メソッド

public:
 bool Unregister(System::Threading::WaitHandle ^ waitObject);

public bool Unregister (System.Threading.WaitHandle? waitObject);

public bool Unregister (System.Threading.WaitHandle waitObject);

[System.Runtime.InteropServices.ComVisible(true)]
public bool Unregister (System.Threading.WaitHandle waitObject);

member this.Unregister : System.Threading.WaitHandle -> bool

[<System.Runtime.InteropServices.ComVisible(true)>]
member this.Unregister : System.Threading.WaitHandle -> bool

Public Function Unregister (waitObject As WaitHandle) As Boolean

パラメーター

戻り値

関数が成功した場合は true。それ以外の場合は false。

属性

ComVisibleAttribute

例

次の例では、 メソッドを使用 Unregister して、待機ハンドルが通知されたためにコールバックが発生した場合にタスクの登録を解除する方法を示します。

この例では、 メソッドを使用して、 RegisterWaitForSingleObject 指定された待機ハンドルが通知されたときに指定されたコールバック メソッドを実行する方法も示します。 この例では、コールバック メソッドは で WaitProc、待機ハンドルは です AutoResetEvent。

この例では、 TaskInfo 実行時にコールバックに渡される情報を保持するクラスを定義します。 この例では、 オブジェクトを TaskInfo 作成し、いくつかの文字列データを割り当てます。 RegisteredWaitHandleコールバック メソッドが にアクセスできるように、 メソッドによってRegisterWaitForSingleObject返される Handle が オブジェクトの TaskInfo フィールドにRegisteredWaitHandle割り当てられます。

コールバック メソッドに渡すオブジェクトとして をTaskInfo指定するだけでなく、 メソッドのRegisterWaitForSingleObject呼び出しでは、タスクが待機する を指定し、WaitOrTimerCallbackコールバック メソッドを表すWaitProcデリゲート、1 秒のタイムアウト間隔、および複数のコールバックを指定AutoResetEventします。

メイン スレッドが メソッドSetを呼び出して をAutoResetEvent通知すると、WaitOrTimerCallbackデリゲートが呼び出されます。 メソッドは WaitProc 、 RegisteredWaitHandle タイムアウトが発生したかどうかを調べます。 待機ハンドルが通知されたためにコールバックが呼び出された場合、 WaitProc メソッドは を RegisteredWaitHandle登録解除し、追加のコールバックを停止します。 タイムアウトの場合、タスクは引き続き待機します。 メソッドは WaitProc 、コンソールにメッセージを出力することによって終了します。

using namespace System;
using namespace System::Threading;

// TaskInfo contains data that will be passed to the callback
// method.
public ref class TaskInfo
{
public:
   TaskInfo()
   {
      Handle = nullptr;
      OtherInfo = "default";
   }

   RegisteredWaitHandle^ Handle;
   String^ OtherInfo;
};

ref class Example
{
public:

   // The callback method executes when the registered wait times out,
   // or when the WaitHandle (in this case AutoResetEvent) is signaled.
   // WaitProc unregisters the WaitHandle the first time the event is 
   // signaled.
   static void WaitProc( Object^ state, bool timedOut )
   {
      
      // The state Object must be cast to the correct type, because the
      // signature of the WaitOrTimerCallback delegate specifies type
      // Object.
      TaskInfo^ ti = static_cast<TaskInfo^>(state);
      String^ cause = "TIMED OUT";
      if (  !timedOut )
      {
         cause = "SIGNALED";
         
         // If the callback method executes because the WaitHandle is
         // signaled, stop future execution of the callback method
         // by unregistering the WaitHandle.
         if ( ti->Handle != nullptr )
                  ti->Handle->Unregister( nullptr );
      }

      Console::WriteLine( "WaitProc( {0}) executes on thread {1}; cause = {2}.", ti->OtherInfo, Thread::CurrentThread->GetHashCode(), cause );
   }

};

int main()
{
   
   // The main thread uses AutoResetEvent to signal the
   // registered wait handle, which executes the callback
   // method.
   AutoResetEvent^ ev = gcnew AutoResetEvent( false );
   TaskInfo^ ti = gcnew TaskInfo;
   ti->OtherInfo = "First task";
   
   // The TaskInfo for the task includes the registered wait
   // handle returned by RegisterWaitForSingleObject.  This
   // allows the wait to be terminated when the object has
   // been signaled once (see WaitProc).
   ti->Handle = ThreadPool::RegisterWaitForSingleObject( ev, gcnew WaitOrTimerCallback( Example::WaitProc ), ti, 1000, false );
   
   // The main thread waits three seconds, to demonstrate the
   // time-outs on the queued thread, and then signals.
   Thread::Sleep( 3100 );
   Console::WriteLine( "Main thread signals." );
   ev->Set();
   
   // The main thread sleeps, which should give the callback
   // method time to execute.  If you comment out this line, the
   // program usually ends before the ThreadPool thread can execute.
   Thread::Sleep( 1000 );
   
   // If you start a thread yourself, you can wait for it to end
   // by calling Thread::Join.  This option is not available with 
   // thread pool threads.
   return 0;
}

using System;
using System.Threading;

// TaskInfo contains data that will be passed to the callback
// method.
public class TaskInfo {
    public RegisteredWaitHandle Handle = null;
    public string OtherInfo = "default";
}

public class Example {
    public static void Main(string[] args) {
        // The main thread uses AutoResetEvent to signal the
        // registered wait handle, which executes the callback
        // method.
        AutoResetEvent ev = new AutoResetEvent(false);

        TaskInfo ti = new TaskInfo();
        ti.OtherInfo = "First task";
        // The TaskInfo for the task includes the registered wait
        // handle returned by RegisterWaitForSingleObject.  This
        // allows the wait to be terminated when the object has
        // been signaled once (see WaitProc).
        ti.Handle = ThreadPool.RegisterWaitForSingleObject(
            ev,
            new WaitOrTimerCallback(WaitProc),
            ti,
            1000,
            false
        );

        // The main thread waits three seconds, to demonstrate the
        // time-outs on the queued thread, and then signals.
        Thread.Sleep(3100);
        Console.WriteLine("Main thread signals.");
        ev.Set();

        // The main thread sleeps, which should give the callback
        // method time to execute.  If you comment out this line, the
        // program usually ends before the ThreadPool thread can execute.
        Thread.Sleep(1000);
        // If you start a thread yourself, you can wait for it to end
        // by calling Thread.Join.  This option is not available with 
        // thread pool threads.
    }
   
    // The callback method executes when the registered wait times out,
    // or when the WaitHandle (in this case AutoResetEvent) is signaled.
    // WaitProc unregisters the WaitHandle the first time the event is 
    // signaled.
    public static void WaitProc(object state, bool timedOut) {
        // The state object must be cast to the correct type, because the
        // signature of the WaitOrTimerCallback delegate specifies type
        // Object.
        TaskInfo ti = (TaskInfo) state;

        string cause = "TIMED OUT";
        if (!timedOut) {
            cause = "SIGNALED";
            // If the callback method executes because the WaitHandle is
            // signaled, stop future execution of the callback method
            // by unregistering the WaitHandle.
            if (ti.Handle != null)
                ti.Handle.Unregister(null);
        } 

        Console.WriteLine("WaitProc( {0} ) executes on thread {1}; cause = {2}.",
            ti.OtherInfo, 
            Thread.CurrentThread.GetHashCode().ToString(), 
            cause
        );
    }
}

Imports System.Threading

' TaskInfo contains data that will be passed to the callback
' method.
Public Class TaskInfo
    public Handle As RegisteredWaitHandle = Nothing
    public OtherInfo As String = "default"
End Class

Public Class Example

    <MTAThread> _
    Public Shared Sub Main()
        ' The main thread uses AutoResetEvent to signal the
        ' registered wait handle, which executes the callback
        ' method.
        Dim ev As New AutoResetEvent(false)

        Dim ti As New TaskInfo()
        ti.OtherInfo = "First task"
        ' The TaskInfo for the task includes the registered wait
        ' handle returned by RegisterWaitForSingleObject.  This
        ' allows the wait to be terminated when the object has
        ' been signaled once (see WaitProc).
        ti.Handle = ThreadPool.RegisterWaitForSingleObject( _
            ev, _
            New WaitOrTimerCallback(AddressOf WaitProc), _
            ti, _
            1000, _
            false _
        )

        ' The main thread waits about three seconds, to demonstrate 
        ' the time-outs on the queued task, and then signals.
        Thread.Sleep(3100)
        Console.WriteLine("Main thread signals.")
        ev.Set()

        ' The main thread sleeps, which should give the callback
        ' method time to execute.  If you comment out this line, the
        ' program usually ends before the ThreadPool thread can execute.
        Thread.Sleep(1000)
        ' If you start a thread yourself, you can wait for it to end
        ' by calling Thread.Join.  This option is not available with 
        ' thread pool threads.
    End Sub
   
    ' The callback method executes when the registered wait times out,
    ' or when the WaitHandle (in this case AutoResetEvent) is signaled.
    ' WaitProc unregisters the WaitHandle the first time the event is 
    ' signaled.
    Public Shared Sub WaitProc(state As Object, timedOut As Boolean)
        ' The state object must be cast to the correct type, because the
        ' signature of the WaitOrTimerCallback delegate specifies type
        ' Object.
        Dim ti As TaskInfo = CType(state, TaskInfo)

        Dim cause As String = "TIMED OUT"
        If Not timedOut Then
            cause = "SIGNALED"
            ' If the callback method executes because the WaitHandle is
            ' signaled, stop future execution of the callback method
            ' by unregistering the WaitHandle.
            If Not ti.Handle Is Nothing Then
                ti.Handle.Unregister(Nothing)
            End If
        End If 

        Console.WriteLine("WaitProc( {0} ) executes on thread {1}; cause = {2}.", _
            ti.OtherInfo, _
            Thread.CurrentThread.GetHashCode().ToString(), _
            cause _
        )
    End Sub
End Class

注釈

が指定されている場合 waitObject は、 が正常に登録解除された場合 RegisteredWaitHandle にのみ通知されます。 の実行時にコールバック メソッドが進行中 Unregister の場合、 waitObject はコールバック メソッドが完了するまでシグナル通知されません。 特に、コールバック メソッドが を実行UnregisterwaitObjectする場合、そのコールバック メソッドが完了するまで通知されません。

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