“添加事件处理程序失败”处理来自 COM 的事件时

Question

我有一个 COM 服务器和一个调用它的 Silverlight (OOTB) 应用程序。我最近对 ​​COM 服务器进行了一些重构，我设法破坏了服务器和客户端之间的事件处理，但我不知道如何破坏它。这是我现在所拥有的：

服务器

namespace ServerNS
{
    [Guid("8FFF7AAE-B162-42C2-9F70-269D285CF622")]
    [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
    [ComVisible(true)]
    interface IServerEvents
    {
        [DispId(1)]
        void MyEvent(MyContainer container);
    }

    [Guid("D2F3738D-DD23-472F-9D36-4136E1196890")]
    [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)]
    [ComVisible(true)]
    public interface IServer
    {
        ...
    }

    [Guid("77253016-1A2A-43CC-A360-04519A4F50F5")]
    [ClassInterface(ClassInterfaceType.None)]
    [ComSourceInterfaces(typeof(IServerEvents))]
    [ProgId("Server.MyServer")]
    [ComVisible(true)]
    public class Server : IServer
    {
        public event MyEventHandler MyEvent;

        public void Trigger(MyContainer container)
        {
            if (MyEvent != null)
            {
                MyEvent(container);
            }
        }
    }
}

客户端

namespace ClientNS
{
    public class Client
    {
        public void Init()
        {
            dynamic comObj = AutomationFactory.CreateObject("Server.MyServer");
            AutomationEvent evt = AutomationFactory.GetEvent(comObj, "MyEvent");

            evt.EventRaised += (sender, e) =>
            {
                //Do Stuff
            }; //Exception occurs here.
        }
    }
}

错误 当我尝试将事件处理程序添加到 AutomationEvent 时，出现此异常。这在我重构（添加 IServerEvents 接口）之前就有效了。 comObj 是一个合法的实例 - 我可以在其上调用其他 COM 方法 - 所以我无法弄清楚为什么它似乎找不到该事件；或者如果这是错误的“某件事失败”部分，如何找出失败的原因。

System.Exception was unhandled by user code
  Message=Failed to add event handler. Possible reasons include: the object does not support this or any events, or something failed while adding the event.
  StackTrace:
       at MS.Internal.Error.MarshalXresultAsException(UInt32 hr, COMExceptionBehavior comExceptionBehavior)
       at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
       at MS.Internal.ComAutomation.ComAutomationNative.ConnectEvent(IntPtr nativePeer, String eventName, RaiseComAutomationEventDelegate raiseComAutomationEventDelegate)
       at MS.Internal.ComAutomation.ComAutomationObject.ConnectEvent(String name)
       at System.Runtime.InteropServices.Automation.AutomationEvent.UpdateConnection()
       at System.Runtime.InteropServices.Automation.AutomationEvent.add_EventRaised(EventHandler`1 value)
       at ClientNS.Client.Init()
       at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
       at System.ComponentModel.BackgroundWorker.OnRun(Object argument)

Answer 1

事实证明，问题在于该接口未声明为“公共” - 因此接口需要如下所示：

public interface IServerEvents
{
    [DispId(1)]
    void MyEvent(MyContainer container);
}

Answer 2

//DHTMLEventHandler.cs 

using System.Runtime.InteropServices;
using mshtml;

namespace BHO
{
    /// 
    /// Generic Event handler for HTML DOM objects.
    /// Handles a basic event object which receives an IHTMLEventObj which
    /// applies to all document events raised.
    /// 

[ComVisible(true)]
public class DHTMLEventHandler
{
    public DHTMLEvent Handler;
    IHTMLDocument2 Document;


    public DHTMLEventHandler(IHTMLDocument2 doc)
    {
        this.Document = doc;
    }
    [DispId(0)]
    public void Call()
    {
        Handler(Document.parentWindow.@event);
    }
}

/// 
/// Generic HTML DOM Event method handler.
/// 
public delegate void DHTMLEvent(IHTMLEventObj e);

添加

在OnDocumentComplete中

IHTMLElement htmlElement = document.getElementById("ele");
DHTMLEventHandler Handler = new DHTMLEventHandler((IHTMLDocument2)webBrowser.Document);
Handler.Handler += new DHTMLEvent(Dummy_OnClick);
htmlElement.onclick = Handler;

新方法来处理点击事件

void Dummy_OnClick(IHTMLEventObj e){
// DO Action 
}