AutoResetEvent Klasse

Definition

public ref class AutoResetEvent sealed : System::Threading::EventWaitHandle

public ref class AutoResetEvent sealed : System::Threading::WaitHandle

public sealed class AutoResetEvent : System.Threading.EventWaitHandle

public sealed class AutoResetEvent : System.Threading.WaitHandle

[System.Runtime.InteropServices.ComVisible(true)]
public sealed class AutoResetEvent : System.Threading.EventWaitHandle

type AutoResetEvent = class
    inherit EventWaitHandle

type AutoResetEvent = class
    inherit WaitHandle

[<System.Runtime.InteropServices.ComVisible(true)>]
type AutoResetEvent = class
    inherit EventWaitHandle

Public NotInheritable Class AutoResetEvent
Inherits EventWaitHandle

Public NotInheritable Class AutoResetEvent
Inherits WaitHandle

Vererbung

Object

WaitHandle

EventWaitHandle

AutoResetEvent

Vererbung

Object

MarshalByRefObject

WaitHandle

EventWaitHandle

AutoResetEvent

Vererbung

Object

MarshalByRefObject

WaitHandle

AutoResetEvent

Attribute

ComVisibleAttribute

Beispiele

Im folgenden Beispiel wird gezeigt, wie sie AutoResetEvent verwenden, um jeweils einen Thread freizugeben, indem die Set-Methode (auf der Basisklasse) jedes Mal aufgerufen wird, wenn der Benutzer die EINGABETASTE Taste drückt. Das Beispiel startet drei Threads, die auf eine AutoResetEvent warten, die im signalierten Zustand erstellt wurde. Der erste Thread wird sofort freigegeben, da sich der AutoResetEvent bereits im signalierten Zustand befindet. Dadurch wird der AutoResetEvent auf den nicht signalfreien Zustand zurückgesetzt, sodass nachfolgende Threads blockiert werden. Die blockierten Threads werden erst freigegeben, wenn der Benutzer sie einzeln loslässt, indem er die EINGABETASTE TASTE drückt.

Nachdem die Threads vom ersten AutoResetEventfreigegeben wurden, warten sie auf eine andere AutoResetEvent, die im nicht signalgesteuerten Zustand erstellt wurde. Alle drei Threads blockieren, sodass die Set-Methode dreimal aufgerufen werden muss, um sie alle freizugeben.

using namespace System;
using namespace System::Threading;

ref class Example
{
private:
    static AutoResetEvent^ event_1 = gcnew AutoResetEvent(true);
    static AutoResetEvent^ event_2 = gcnew AutoResetEvent(false);

    static void ThreadProc()
    {
        String^ name = Thread::CurrentThread->Name;

        Console::WriteLine("{0} waits on AutoResetEvent #1.", name);
        event_1->WaitOne();
        Console::WriteLine("{0} is released from AutoResetEvent #1.", name);

        Console::WriteLine("{0} waits on AutoResetEvent #2.", name);
        event_2->WaitOne();
        Console::WriteLine("{0} is released from AutoResetEvent #2.", name);

        Console::WriteLine("{0} ends.", name);
    }

public:
    static void Demo()
    {
        Console::WriteLine("Press Enter to create three threads and start them.\r\n" +
                           "The threads wait on AutoResetEvent #1, which was created\r\n" +
                           "in the signaled state, so the first thread is released.\r\n" +
                           "This puts AutoResetEvent #1 into the unsignaled state.");
        Console::ReadLine();
            
        for (int i = 1; i < 4; i++)
        {
            Thread^ t = gcnew Thread(gcnew ThreadStart(&ThreadProc));
            t->Name = "Thread_" + i;
            t->Start();
        }
        Thread::Sleep(250);

        for (int i = 0; i < 2; i++)
        {
            Console::WriteLine("Press Enter to release another thread.");
            Console::ReadLine();
            event_1->Set();
            Thread::Sleep(250);
        }

        Console::WriteLine("\r\nAll threads are now waiting on AutoResetEvent #2.");
        for (int i = 0; i < 3; i++)
        {
            Console::WriteLine("Press Enter to release a thread.");
            Console::ReadLine();
            event_2->Set();
            Thread::Sleep(250);
        }

        // Visual Studio: Uncomment the following line.
        //Console::Readline();
    }
};

void main()
{
    Example::Demo();
}

/* This example produces output similar to the following:

Press Enter to create three threads and start them.
The threads wait on AutoResetEvent #1, which was created
in the signaled state, so the first thread is released.
This puts AutoResetEvent #1 into the unsignaled state.

Thread_1 waits on AutoResetEvent #1.
Thread_1 is released from AutoResetEvent #1.
Thread_1 waits on AutoResetEvent #2.
Thread_3 waits on AutoResetEvent #1.
Thread_2 waits on AutoResetEvent #1.
Press Enter to release another thread.

Thread_3 is released from AutoResetEvent #1.
Thread_3 waits on AutoResetEvent #2.
Press Enter to release another thread.

Thread_2 is released from AutoResetEvent #1.
Thread_2 waits on AutoResetEvent #2.

All threads are now waiting on AutoResetEvent #2.
Press Enter to release a thread.

Thread_2 is released from AutoResetEvent #2.
Thread_2 ends.
Press Enter to release a thread.

Thread_1 is released from AutoResetEvent #2.
Thread_1 ends.
Press Enter to release a thread.

Thread_3 is released from AutoResetEvent #2.
Thread_3 ends.
 */

using System;
using System.Threading;

// Visual Studio: Replace the default class in a Console project with 
//                the following class.
class Example
{
    private static AutoResetEvent event_1 = new AutoResetEvent(true);
    private static AutoResetEvent event_2 = new AutoResetEvent(false);

    static void Main()
    {
        Console.WriteLine("Press Enter to create three threads and start them.\r\n" +
                          "The threads wait on AutoResetEvent #1, which was created\r\n" +
                          "in the signaled state, so the first thread is released.\r\n" +
                          "This puts AutoResetEvent #1 into the unsignaled state.");
        Console.ReadLine();
            
        for (int i = 1; i < 4; i++)
        {
            Thread t = new Thread(ThreadProc);
            t.Name = "Thread_" + i;
            t.Start();
        }
        Thread.Sleep(250);

        for (int i = 0; i < 2; i++)
        {
            Console.WriteLine("Press Enter to release another thread.");
            Console.ReadLine();
            event_1.Set();
            Thread.Sleep(250);
        }

        Console.WriteLine("\r\nAll threads are now waiting on AutoResetEvent #2.");
        for (int i = 0; i < 3; i++)
        {
            Console.WriteLine("Press Enter to release a thread.");
            Console.ReadLine();
            event_2.Set();
            Thread.Sleep(250);
        }

        // Visual Studio: Uncomment the following line.
        //Console.Readline();
    }

    static void ThreadProc()
    {
        string name = Thread.CurrentThread.Name;

        Console.WriteLine("{0} waits on AutoResetEvent #1.", name);
        event_1.WaitOne();
        Console.WriteLine("{0} is released from AutoResetEvent #1.", name);

        Console.WriteLine("{0} waits on AutoResetEvent #2.", name);
        event_2.WaitOne();
        Console.WriteLine("{0} is released from AutoResetEvent #2.", name);

        Console.WriteLine("{0} ends.", name);
    }
}

/* This example produces output similar to the following:

Press Enter to create three threads and start them.
The threads wait on AutoResetEvent #1, which was created
in the signaled state, so the first thread is released.
This puts AutoResetEvent #1 into the unsignaled state.

Thread_1 waits on AutoResetEvent #1.
Thread_1 is released from AutoResetEvent #1.
Thread_1 waits on AutoResetEvent #2.
Thread_3 waits on AutoResetEvent #1.
Thread_2 waits on AutoResetEvent #1.
Press Enter to release another thread.

Thread_3 is released from AutoResetEvent #1.
Thread_3 waits on AutoResetEvent #2.
Press Enter to release another thread.

Thread_2 is released from AutoResetEvent #1.
Thread_2 waits on AutoResetEvent #2.

All threads are now waiting on AutoResetEvent #2.
Press Enter to release a thread.

Thread_2 is released from AutoResetEvent #2.
Thread_2 ends.
Press Enter to release a thread.

Thread_1 is released from AutoResetEvent #2.
Thread_1 ends.
Press Enter to release a thread.

Thread_3 is released from AutoResetEvent #2.
Thread_3 ends.
 */

Imports System.Threading

' Visual Studio: Replace the default class in a Console project with 
'                the following class.
Class Example

    Private Shared event_1 As New AutoResetEvent(True)
    Private Shared event_2 As New AutoResetEvent(False)

    <MTAThread()> _
    Shared Sub Main()
    
        Console.WriteLine("Press Enter to create three threads and start them." & vbCrLf & _
                          "The threads wait on AutoResetEvent #1, which was created" & vbCrLf & _
                          "in the signaled state, so the first thread is released." & vbCrLf & _
                          "This puts AutoResetEvent #1 into the unsignaled state.")
        Console.ReadLine()
            
        For i As Integer = 1 To 3
            Dim t As New Thread(AddressOf ThreadProc)
            t.Name = "Thread_" & i
            t.Start()
        Next
        Thread.Sleep(250)

        For i As Integer = 1 To 2
            Console.WriteLine("Press Enter to release another thread.")
            Console.ReadLine()

            event_1.Set()
            Thread.Sleep(250)
        Next

        Console.WriteLine(vbCrLf & "All threads are now waiting on AutoResetEvent #2.")
        For i As Integer = 1 To 3
            Console.WriteLine("Press Enter to release a thread.")
            Console.ReadLine()

            event_2.Set()
            Thread.Sleep(250)
        Next

        ' Visual Studio: Uncomment the following line.
        'Console.Readline()
    End Sub

    Shared Sub ThreadProc()
    
        Dim name As String = Thread.CurrentThread.Name

        Console.WriteLine("{0} waits on AutoResetEvent #1.", name)
        event_1.WaitOne()
        Console.WriteLine("{0} is released from AutoResetEvent #1.", name)

        Console.WriteLine("{0} waits on AutoResetEvent #2.", name)
        event_2.WaitOne()
        Console.WriteLine("{0} is released from AutoResetEvent #2.", name)

        Console.WriteLine("{0} ends.", name)
    End Sub
End Class

' This example produces output similar to the following:
'
'Press Enter to create three threads and start them.
'The threads wait on AutoResetEvent #1, which was created
'in the signaled state, so the first thread is released.
'This puts AutoResetEvent #1 into the unsignaled state.
'
'Thread_1 waits on AutoResetEvent #1.
'Thread_1 is released from AutoResetEvent #1.
'Thread_1 waits on AutoResetEvent #2.
'Thread_3 waits on AutoResetEvent #1.
'Thread_2 waits on AutoResetEvent #1.
'Press Enter to release another thread.
'
'Thread_3 is released from AutoResetEvent #1.
'Thread_3 waits on AutoResetEvent #2.
'Press Enter to release another thread.
'
'Thread_2 is released from AutoResetEvent #1.
'Thread_2 waits on AutoResetEvent #2.
'
'All threads are now waiting on AutoResetEvent #2.
'Press Enter to release a thread.
'
'Thread_2 is released from AutoResetEvent #2.
'Thread_2 ends.
'Press Enter to release a thread.
'
'Thread_1 is released from AutoResetEvent #2.
'Thread_1 ends.
'Press Enter to release a thread.
'
'Thread_3 is released from AutoResetEvent #2.
'Thread_3 ends.

Hinweise

Sie verwenden AutoResetEvent, ManualResetEventund EventWaitHandle für threadinteraktion (oder Threadsignalisierung). Weitere Informationen finden Sie unter Threadinteraktion.

Ein Thread wartet auf ein Signal, indem AutoResetEvent.WaitOneaufgerufen wird. Wenn sich der AutoResetEvent im nicht signalisierten Zustand befindet, wird der Thread blockiert, bis AutoResetEvent.Set aufgerufen wird. Das Aufrufen von Set Signalen AutoResetEvent, einen Wartethread freizugeben. AutoResetEvent bleibt signalisiert, bis Reset aufgerufen wird oder ein einzelner Wartethread losgelassen wird, zu dem zeitpunkt, zu dem er automatisch zum nicht signalisierten Zustand zurückkehrt.

Wenn keine Threads warten, wenn die AutoResetEvent in einen signalisierten Zustand wechselt, bleibt der Zustand signalisiert, bis ein Thread das Signal beobachtet (durch Aufrufen WaitOne). Dieser Thread blockiert nicht: Der AutoResetEvent gibt den Thread sofort frei und kehrt zum nicht signalisierten Zustand zurück.

Sie können den Anfangszustand eines AutoResetEvent steuern, indem Sie einen booleschen Wert an den Konstruktor übergeben: true, wenn der Anfangszustand signalisiert ist und andernfalls false.

AutoResetEvent können auch mit den methoden staticWaitAll und WaitAny verwendet werden.

AutoResetEvent wird von der EventWaitHandle Klasse abgeleitet. Ein AutoResetEvent entspricht funktional einem mit EventResetMode.AutoReseterstellten EventWaitHandle.

Konstruktoren

Felder

Eigenschaften

Methoden

Explizite Schnittstellenimplementierungen

Erweiterungsmethoden

Gilt für:

Threadsicherheit

Diese Klasse ist threadsicher.

Weitere Informationen

• WaitHandle
• verwalteten Threading-
• Übersicht über Synchronisierungsgrundtypen