AutoResetEvent 類別

參考

定義

命名空間:: System.Threading

組件:: System.Threading.dll

組件:: mscorlib.dll

組件:: netstandard.dll

來源:: AutoResetEvent.cs

來源:: AutoResetEvent.cs

來源:: AutoResetEvent.cs

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

表示線程同步處理事件，當發出訊號時，釋放一個等候中的線程，然後自動重設。此類別無法獲得繼承。

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

繼承: Object

WaitHandle

EventWaitHandle
AutoResetEvent

繼承: Object

MarshalByRefObject

WaitHandle

EventWaitHandle
AutoResetEvent

繼承: Object

MarshalByRefObject

WaitHandle
AutoResetEvent

屬性: ComVisibleAttribute

範例

下列範例示範如何使用 AutoResetEvent 一次釋放一個執行緒，方式是透過每次使用者按下 Enter 鍵時呼叫 Set 方法 (在基底類別中)。此範例會啟動三個執行緒，等候在已收到信號狀態中建立的 AutoResetEvent。第一個執行緒會被立即釋放，因為 AutoResetEvent 已處於收到信號的狀態。這會將 AutoResetEvent 重設為未收到信號的狀態，以便封鎖後續的執行緒。已封鎖的執行緒不會被釋放，直到使用者一次按 Enter 鍵釋放一個。

從第一個 AutoResetEvent釋放線程之後，它們會等候另一個 AutoResetEvent 處於非訊號狀態建立的線程。這三個線程區塊，因此 Set 必須呼叫方法三次，才能全部釋放它們。

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.

備註

AutoResetEvent您可以使用、 ManualResetEvent和 EventWaitHandle 進行線程互動 (或線程訊號) 。如需詳細資訊，請參閱線程互動。

線程會呼叫 AutoResetEvent.WaitOne 來等候訊號。 AutoResetEvent如果處於非訊號狀態，線程會封鎖直到呼叫 AutoResetEvent.Set 為止。呼叫 Set 訊號 AutoResetEvent 以釋放等候的線程。 AutoResetEvent 會保持訊號，直到 Reset 呼叫或釋放單一等候線程為止，此時會自動回到非訊號狀態。

如果沒有線程在進入訊號狀態時 AutoResetEvent 等候，狀態會維持訊號，直到線程藉由呼叫 WaitOne) 觀察訊號 (為止。該線程不會封鎖：會 AutoResetEvent 立即釋放線程，並返回非訊號狀態。

重要

不保證每次呼叫 Set 方法都會釋放線程。如果兩個呼叫太接近，因此第二個呼叫會在釋放線程之前發生，則只會釋放一個線程。就像第二次呼叫未發生一樣。此外，如果在 Set 沒有等候的線程且 AutoResetEvent 已經發出訊號時呼叫，則呼叫不會有任何作用。

您可以藉由將布林值傳遞至建構函式來控制的初始狀態 AutoResetEvent ： true 如果初始狀態已發出訊號， false 則為，否則為。

AutoResetEvent 也可以搭配 staticWaitAll 和 WaitAny 方法使用。

AutoResetEvent 衍生自 EventWaitHandle 類別。 AutoResetEvent的功能相當於使用 EventResetMode.AutoReset所建立的 EventWaitHandle 。

注意

AutoResetEvent不同於類別，類別EventWaitHandle提供具名系統同步處理事件的存取權。

重要

此型別代表 IDisposable 介面。當您完成使用型別時，您應該直接或間接處置它。若要直接處置型別，請呼叫其 try/catch 區塊中的 Dispose 方法。若要間接處置它，請使用語言建構函式，例如 using (在 C# 中) 或 Using (在 Visual Basic 中)。 For more information, see the "Using an Object that Implements IDisposable" section on the IDisposable interface page.

建構函式

AutoResetEvent(Boolean)

使用布林值 (Boolean) 來初始化 AutoResetEvent 類別的新執行個體，指出初始狀態是否設定為信號狀態。

欄位

WaitTimeout

表示 WaitAny(WaitHandle[], Int32, Boolean) 作業在發出任何等候控制代碼信號之前便已逾時。這個欄位為常數。

(繼承來源 WaitHandle)

屬性

Handle	已淘汰. 已淘汰. 取得或設定原生 (Native) 的作業系統控制代碼。 (繼承來源 WaitHandle)
SafeWaitHandle	取得或設定原生 (Native) 的作業系統控制代碼。 (繼承來源 WaitHandle)

方法

Close()	釋放目前 WaitHandle 所持有的全部資源。 (繼承來源 WaitHandle)
CreateObjRef(Type)	建立包含所有相關資訊的物件，這些資訊是產生用來與遠端物件通訊的所需 Proxy。 (繼承來源 MarshalByRefObject)
Dispose()	釋放 WaitHandle 類別目前的執行個體所使用的全部資源。 (繼承來源 WaitHandle)
Dispose(Boolean)	當在衍生類別中覆寫時，釋放 WaitHandle 所使用的 Unmanaged 資源，並選擇性釋放 Managed 資源。 (繼承來源 WaitHandle)
Equals(Object)	判斷指定的物件是否等於目前的物件。 (繼承來源 Object)
GetAccessControl()	取得 EventWaitHandleSecurity 物件，此物件代表由目前 EventWaitHandle 物件所表示的具名系統事件的存取控制安全性。 (繼承來源 EventWaitHandle)
GetHashCode()	做為預設雜湊函式。 (繼承來源 Object)
GetLifetimeService()	已淘汰. 擷取控制這個執行個體存留期 (Lifetime) 原則的目前存留期服務物件。 (繼承來源 MarshalByRefObject)
GetType()	取得目前執行個體的 Type。 (繼承來源 Object)
InitializeLifetimeService()	已淘汰. 取得存留期服務物件，以控制這個執行個體的存留期原則。 (繼承來源 MarshalByRefObject)
MemberwiseClone()	建立目前 Object 的淺層複製。 (繼承來源 Object)
MemberwiseClone(Boolean)	建立目前 MarshalByRefObject 物件的淺層複本。 (繼承來源 MarshalByRefObject)
Reset()	將事件的狀態設定為未收到信號，會造成執行緒封鎖。
Reset()	將事件的狀態設定為未收到信號，會造成執行緒封鎖。 (繼承來源 EventWaitHandle)
Set()	將事件的狀態設定為收到信號，允許最多一個等候執行緒繼續執行。
Set()	將事件的狀態設定為未收到信號，讓一個或多個等候執行緒繼續執行。 (繼承來源 EventWaitHandle)
SetAccessControl(EventWaitHandleSecurity)	為具名系統事件設定存取控制安全性。 (繼承來源 EventWaitHandle)
ToString()	傳回代表目前物件的字串。 (繼承來源 Object)
WaitOne()	封鎖目前的執行緒，直到目前的 WaitHandle 收到訊號為止。 (繼承來源 WaitHandle)
WaitOne(Int32)	封鎖目前執行緒，直到目前的 WaitHandle 收到信號為止，使用 32 位元帶正負號的整數來指定時間間隔 (以毫秒為單位)。 (繼承來源 WaitHandle)
WaitOne(Int32, Boolean)	封鎖目前執行緒，直到目前的 WaitHandle 收到信號為止，使用 32 位元帶正負號的整數來指定時間間隔，並指定是否要先離開同步處理網域，再開始等候。 (繼承來源 WaitHandle)
WaitOne(TimeSpan)	封鎖目前執行緒，直到目前執行個體收到信號為止，使用 TimeSpan 來指定時間間隔。 (繼承來源 WaitHandle)
WaitOne(TimeSpan, Boolean)	封鎖目前執行緒，直到目前執行個體收到信號為止，使用 TimeSpan 來指定時間間隔，並指定是否要先離開同步處理網域，再開始等候。 (繼承來源 WaitHandle)

明確介面實作

IDisposable.Dispose()

此 API 支援此產品基礎結構，但無法直接用於程式碼之中。

釋放 WaitHandle 所使用的所有資源。

(繼承來源 WaitHandle)

擴充方法

GetAccessControl(EventWaitHandle)	傳回所指定 `handle` 的安全性描述元。
SetAccessControl(EventWaitHandle, EventWaitHandleSecurity)	設定所指定事件等候控制代碼的安全性描述元。
GetSafeWaitHandle(WaitHandle)	取得原生作業系統等候控制代碼的安全控制代碼。
SetSafeWaitHandle(WaitHandle, SafeWaitHandle)	設定原生作業系統等候控制代碼的安全控制代碼。

適用於

執行緒安全性

這個類別是安全線程。

AutoResetEvent 類別

定義

範例

備註

建構函式

欄位

屬性

方法

明確介面實作

擴充方法

適用於

執行緒安全性

另請參閱

意見反應

其他資源