如何在多线程或基于 wcf 服务的应用程序中正确使用事件？

Question

我有提供一些实时事件的设备，制造商给了我一个 dll 用于使用该事件并基于该设备开发程序。 这是该 dll 的一些属性和事件：

    [ClassInterface(0)]
[ComSourceInterfaces("zkemkeeper._IZKEMEvents")]
[Guid("00853A19-BD51-419B-9269-2DABE57EB61F")]
[TypeLibType(2)]
public class CZKEMClass : IZKEM, CZKEM, _IZKEMEvents_Event
{
    public CZKEMClass();

    [DispId(79)]
    public virtual int AccGroup { get; set; }
    [DispId(76)]
    public virtual int BASE64 { get; set; }
    [DispId(2)]
    public virtual int CommPort { get; set; }
    [DispId(64)]
    public virtual int ConvertBIG5 { get; set; }
    [DispId(123)]
    public virtual int MachineNumber { get; set; }
    [DispId(78)]
    public virtual uint PIN2 { get; set; }
    [DispId(102)]
    public virtual int PINWidth { get; }
    [DispId(241)]
    public virtual int PullMode { get; set; }
    [DispId(1)]
    public virtual bool ReadMark { get; set; }
    [DispId(191)]
    public virtual int SSRPin { get; }

    public virtual event _IZKEMEvents_OnAlarmEventHandler OnAlarm;
    public virtual event _IZKEMEvents_OnAttTransactionEventHandler OnAttTransaction;
    public virtual event _IZKEMEvents_OnAttTransactionExEventHandler OnAttTransactionEx;
    public virtual event _IZKEMEvents_OnConnectedEventHandler OnConnected;
    public virtual event _IZKEMEvents_OnDeleteTemplateEventHandler OnDeleteTemplate;
    public virtual event _IZKEMEvents_OnDisConnectedEventHandler OnDisConnected;
    public virtual event _IZKEMEvents_OnDoorEventHandler OnDoor;
    public virtual event _IZKEMEvents_OnEMDataEventHandler OnEMData;
    public virtual event _IZKEMEvents_OnEmptyCardEventHandler OnEmptyCard;
    public virtual event _IZKEMEvents_OnEnrollFingerEventHandler OnEnrollFinger;
    public virtual event _IZKEMEvents_OnEnrollFingerExEventHandler OnEnrollFingerEx;
    public virtual event _IZKEMEvents_OnFingerEventHandler OnFinger;
    public virtual event _IZKEMEvents_OnFingerFeatureEventHandler OnFingerFeature;
    public virtual event _IZKEMEvents_OnHIDNumEventHandler OnHIDNum;
    public virtual event _IZKEMEvents_OnKeyPressEventHandler OnKeyPress;
    public virtual event _IZKEMEvents_OnNewUserEventHandler OnNewUser;
    public virtual event _IZKEMEvents_OnVerifyEventHandler OnVerify;
    public virtual event _IZKEMEvents_OnWriteCardEventHandler OnWriteCard;

他们给了我一个这样的实时事件的示例代码：

if (this.RegEvent(this.iNo, 65535))//Here you can register the realtime events that you want to be triggered(the parameters 65535 means registering all)
        {
            _zkemkeeper.OnFinger += new zkemkeeper._IZKEMEvents_OnFingerEventHandler(axCZKEM1_OnFinger);
            _zkemkeeper.OnVerify += new zkemkeeper._IZKEMEvents_OnVerifyEventHandler(axCZKEM1_OnVerify);
            _zkemkeeper.OnAttTransactionEx += new zkemkeeper._IZKEMEvents_OnAttTransactionExEventHandler(axCZKEM1_OnAttTransactionEx);
            _zkemkeeper.OnFingerFeature += new zkemkeeper._IZKEMEvents_OnFingerFeatureEventHandler(axCZKEM1_OnFingerFeature);
            _zkemkeeper.OnEnrollFingerEx += new zkemkeeper._IZKEMEvents_OnEnrollFingerExEventHandler(axCZKEM1_OnEnrollFingerEx);
            _zkemkeeper.OnDeleteTemplate += new zkemkeeper._IZKEMEvents_OnDeleteTemplateEventHandler(axCZKEM1_OnDeleteTemplate);
            _zkemkeeper.OnNewUser += new zkemkeeper._IZKEMEvents_OnNewUserEventHandler(axCZKEM1_OnNewUser);
            _zkemkeeper.OnHIDNum += new zkemkeeper._IZKEMEvents_OnHIDNumEventHandler(axCZKEM1_OnHIDNum);
            _zkemkeeper.OnAlarm += new zkemkeeper._IZKEMEvents_OnAlarmEventHandler(axCZKEM1_OnAlarm);
            _zkemkeeper.OnDoor += new zkemkeeper._IZKEMEvents_OnDoorEventHandler(axCZKEM1_OnDoor);
            _zkemkeeper.OnWriteCard += new zkemkeeper._IZKEMEvents_OnWriteCardEventHandler(axCZKEM1_OnWriteCard);
            _zkemkeeper.OnEmptyCard += new zkemkeeper._IZKEMEvents_OnEmptyCardEventHandler(axCZKEM1_OnEmptyCard);
            _zkemkeeper.m_bRegisteredEvents = true;
            uLog("Ends");
        }

我可以在我的单线程或 Windows 应用程序中使用此示例，它可以正常工作并正确触发实时事件，但是当我在多线程应用程序或服务层（如基本 wcf 服务）中使用它时不工作！ 请帮帮我

Answer 1

在 STA 线程内创建

Thread createComAndMessagePumpThread = new Thread(() =>
{
    //you code here
});
createComAndMessagePumpThread.SetApartmentState(ApartmentState.STA);
createComAndMessagePumpThread.Start();

Answer 2

什么不起作用？

通常会在 IO 线程上提供实时更新。对于 Windows 应用程序，如果您希望与 UI 线程仿射元素交互，则必须将调用编组到 UI 线程上。

Answer 3

这样调用事件将不起作用，因为在线程内引发的事件只会触发该特定线程中的订阅者。您需要使用可以向其他线程发出信号的事件。

我建议通读微软网站上的这个问题板：https://social.msdn.microsoft.com/Forums/en-US/13f30e33-7f61-498e-a91a-ef982a63453c/event-handling-in-multithreaded-apps?forum=netfxbcl

答案提供了详细信息以及如何创建可以有效地向其他线程发出信号的事件。