EventHandle.WaitOne + WebBrowser =等待DocumentComplete时出现死锁

Question

EventHandle.WaitOne + WebBrowser =等待DocumentComplete时出现死锁

lic*_*ger 5 c# deadlock webbrowser-control manualresetevent

我在C#-Program中遇到了WebBrowsing自动化的问题.我之前使用过代码来获取BHO,并且它正在运行.但在纯粹的c#程序中,似乎存在某种僵局.我已经指示我的程序点击搜索按钮,然后等待(通过手动重新发送)文档完成信号.但是现在似乎在ManualResetEvent发出超时信号之前不会处理点击搜索按钮.然后单击,并且还会触发DocumentComplete-Event.

对于该程序的结构:WebBrowser-Control是WindowsForm的一部分.WebBrowser控件传递给运行Thread的Class.该类再次将控件传递给另一个类,其中根据加载的webbrowser编程具体行为.

所以在Code中这样看起来:

线程的设置

_runner = new Thread(runner);
_runner.SetApartmentState(ApartmentState.STA);
_runner.IsBackground = true;
_runner.Start();

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用流道法加工
```
b.placeTipp(workStructure);
```
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PlaceTipp方法

public void placeTipp(ref OverallTippStructure tipp)
    {
        _expectedUrl = String.Empty;
        _betUrl = String.Empty;
        _status = BookieStatusType.CHECKLOGIN;

        while (true)
        {
            _mreWaitForAction.Reset();
            checkIETab();

            switch (_status)
            {
                case BookieStatusType.REQUESTWEBSITE:
                    ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Keine IE-Tab vorhanden. Fordere eine an", this.BookieName));
                    //if (RequestIETabEvent != null)
                    //    RequestIETabEvent(this, new EventArgs());
                    _status = BookieStatusType.NAVIGATETOWEBSITE;
                    _mreWaitForAction.Set();
                    break;
                case BookieStatusType.NAVIGATETOWEBSITE:                                                
                    _webBrowser.Navigate(@"http://www.nordicbet.com");
                    break;
                case BookieStatusType.CHECKLOGIN:
                    checkLogin();
                    break;
                case BookieStatusType.LOGINNEEDED:
                    doLogin();
                    break;
                case BookieStatusType.LOGGEDIN:
                    _status = BookieStatusType.SEARCHTIPP;
                    _mreWaitForAction.Set();
                    break;
                case BookieStatusType.SEARCHTIPP:
                    searchTipp(tipp);
                    break;
                case BookieStatusType.NAVTOSB:
                    NavToSB();
                    break;
                case BookieStatusType.GETMARKET:
                    getMarket(tipp);
                    break;
                case BookieStatusType.PLACEBET:
                    placeBet(tipp);
                    break;
                case BookieStatusType.CONFIRMBET:
                    confirmBet();
                    break;
                case BookieStatusType.EXTRACTBETDATA:
                    extractBetId(ref tipp);
                    break;
                case BookieStatusType.FINISHED:
                    return;
            }


            if (!_mreWaitForAction.WaitOne(60000))
            {
                //Sonderüberpüfung be LoginNeeded
                if (_status == BookieStatusType.LOGINNEEDED)
                {
                    //checkLogin();
                    throw new BookieLoginFailedExcpetion();
                }
                //TIMEOUT!
                ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Timeout bei warten auf nächsten Schritt. Status war {1}", this.BookieName, this._status.ToString()));
                throw new BookieTimeoutExcpetion(String.Format("Bookie {0}: Timeout bei dem Warten auf Ereignis", this.BookieName));
            }
        }
    }

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正在发生死锁的SearchTipp-Method:

private void searchTipp(OverallTippStructure tipp)
    {
        if (_webBrowser.InvokeRequired)
        {
            _webBrowser.Invoke(new delegatePlaceBet(searchTipp), new object[] { tipp });
        }
        else
        {
            ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Suche Tipp {1}", this.BookieName, tipp.BookieMatchName));
            _expectedUrl = String.Empty;
            if (!_webBrowser.Url.ToString().StartsWith("https://www.nordicbet.com/eng/sportsbook"))
            {
                ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Nicht auf Sportsbookseite. Navigiere", this.BookieName));
                _status = BookieStatusType.NAVTOSB;
                _mreWaitForAction.Set();
                return;
            }
            _searchCompleted = false;
            HtmlDocument doc = _webBrowser.Document;

            if (doc != null)
            {

                mshtml.IHTMLInputElement elemSearch = (mshtml.IHTMLInputElement)doc.GetElementById("query").DomElement;
                if (elemSearch != null)
                {
                    Thread.Sleep(Delayer.delay(2000, 10000));
                    elemSearch.value = tipp.BookieMatchName;

                    mshtml.IHTMLElement elemSearchButton = (mshtml.IHTMLElement)doc.GetElementById("search_button").DomElement;
                    if (elemSearchButton != null)
                    {
                        Thread.Sleep(Delayer.delay(900, 4000));

                        elemSearchButton.click();
                        //elemSearchButton.InvokeMember("click");

                        if (!_mreWaitForAction.WaitOne(10000)) //Here The Deadlock happens
                        {
                            //Now the click event and therefor the search will be executed
                            ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Suche ist auf Timeout gelaufen", this.BookieName));
                            throw new BookieTimeoutExcpetion(String.Format("Bookie {0}: Suche ist auf Timeout gelaufen", this.BookieName));
                        }                                                        

                        _mreWaitForAction.Reset();
                        HtmlElement spanResult = doc.GetElementById("total_ocs_count");
                        while (spanResult == null)
                        {
                            Thread.Sleep(500);
                            spanResult = doc.GetElementById("total_ocs_count");
                        }

                        int total_ocs_count = 0;
                        if (!Int32.TryParse(spanResult.InnerHtml, out total_ocs_count))
                        {
                            ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Tip {1} nicht gefunden", this.BookieName, tipp.BookieMatchName));
                            throw new BookieTippNotFoundExcpetion(String.Format("Bookie {0}: Tip {1} nicht gefunden", this.BookieName, tipp.BookieMatchName));
                        }

                        if (total_ocs_count <= 0)
                        {
                            ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Tip {1} nicht gefunden", this.BookieName, tipp.BookieMatchName));
                            throw new BookieTippNotFoundExcpetion(String.Format("Bookie {0}: Tip {1} nicht gefunden", this.BookieName, tipp.BookieMatchName));
                        }
                        /*
                    else if (total_ocs_count > 1)
                    {
                        throw new BookieMoreThanOneFoundExcpetion(String.Format("Bookie {0}: Tipp {1} nicht eindeutig", this.BookieName, tipp.BookieMatchName));
                    }
                    */
                        ConsoleWriter.writeToConsole(String.Format("Bookie {0}: Tip {1} gefunden", this.BookieName, tipp.BookieMatchName));
                        _status = BookieStatusType.GETMARKET;
                    }
                }
            }
            _mreWaitForAction.Set();
        }
    }

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有人知道这里发生了什么？

谢谢

lichtbringer

Answer 1

nos*_*tio 3

通过这样做_webBrowser.Invoke(new delegatePlaceBet(searchTipp), new object[] { tipp })，您可以使该searchTipp方法在主 UI 线程上同步执行。WebBrowser这是可以理解的，因为除了创建控件的原始线程之外，您无法从任何线程访问API。

然而，这样做的话，_mreWaitForAction.WaitOne(10000)调用也会在主 UI 线程上执行，从而有效地阻塞消息循环（由启动Application.Run）。WebBrowser需要一个功能性的消息循环，它不断地发送 Windows 消息，否则DocumentCompleted不会被触发，并且您将陷入死锁。

我的理解是，您只需在此处创建另一个线程来组织自动化场景的工作流程。你真的不需要另一个线程。 下面是如何使用/在主 UI 线程上异步完成此操作的示例，下面是在控制台应用程序中使用的示例。asyncawaitWebBrowser

或者，作为解决方法，您可以WaitWithDoEvents从此处使用，如下所示：_mreWaitForAction.WaitWithDoEvents(10000)。它等待句柄，同时仍然发送消息。您应该意识到使用 . 创建嵌套消息循环的潜在影响Application.DoEvents()。

请注意，如果您使用嵌套消息循环，您仍然不需要单独的线程。它将为您提供主 UI 线程上的线性代码工作流程。例子：

private void buttonStart_Click(object sender, EventArgs e)
{
    using (var mre = new ManualResetEvent(false))
    {
        WebBrowserDocumentCompletedEventHandler handler = (s, args) => 
            mre.Set();
        this.webBrowser.DocumentCompleted += handler;
        try
        {
            this.webBrowser.Navigate("http://www.example.com");
            mre.WaitWithDoEvents(10000);
        }
        finally
        {
            this.webBrowser.DocumentCompleted -= handler;
        }
    }
    MessageBox.Show(this.webBrowser.Document.Body.OuterHtml);
}

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尽管正如我上面提到的，您可以更自然地实现相同的目的，并且无需嵌套消息循环，使用async/ await，这是执行此操作的首选方式，IMO。

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