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ObjectDisposedException 被捕获。

无法访问已处置的对象。对象名称：'Form1'。

那是当后台工作人员正在工作时，我单击右上角的 X 红色 X 以关闭应用程序，当它处于工作中间时，有时它会抛出此异常。

System.ObjectDisposedException was caught
  Message=Cannot access a disposed object.
Object name: 'Form1'.
  Source=System.Windows.Forms
  ObjectName=Form1
  StackTrace:
       at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous)
       at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args)
       at System.Windows.Forms.Control.Invoke(Delegate method)
       at GatherLinks.Form1.test(String url, Int32 levels, DoWorkEventArgs eve) in D:\C-Sharp\GatherLinks\GatherLinks\GatherLinks\Form1.cs:line 126
  InnerException:

在这种情况下，第 126 行是：

this.Invoke(new MethodInvoker(delegate { Texts(richTextBox1, " Done " + Environment.NewLine, Color.Red); }));

我应该如何修复/修复此异常以及退出应用程序时应该释放/关闭哪些对象或变量？

测试功能：

private List<string> test(string url, int levels,DoWorkEventArgs eve)
        {
            levels = levelsToCrawl;
            HtmlWeb hw = new HtmlWeb();
            List<string> webSites;
            List<string> csFiles = new List<string>();

            csFiles.Add("temp string to know that something is happening in level = " + levels.ToString());
            csFiles.Add("current site name in this level is : " + url);

            try
            {
                this.Invoke(new MethodInvoker(delegate { Texts(richTextBox1, "Loading The Url:   " + url + "..." , Color.Red); }));
                HtmlAgilityPack.HtmlDocument doc = GetHtmlDoc(url, reqOptions, null);
                if (timeOut == true)
                {
                    this.Invoke(new MethodInvoker(delegate { Texts(richTextBox1, " There Was A TimeOut" + Environment.NewLine , Color.Red); }));
                    timeOut = false;
                    return csFiles;
                }
                else
                {
                    this.Invoke(new MethodInvoker(delegate { Texts(richTextBox1, " Done " + Environment.NewLine, Color.Red); }));
                }
                currentCrawlingSite.Add(url);
                webSites = getLinks(doc);
                removeDupes(webSites);
                removeDuplicates(webSites, currentCrawlingSite);
                removeDuplicates(webSites, sitesToCrawl);
                if (removeExt == true)
                {
                    removeExternals(webSites);
                }
                if (downLoadImages == true)
                {
                    retrieveImages(url);                 }

                if (levels > 0)
                    sitesToCrawl.AddRange(webSites
                this.Invoke(new MethodInvoker(delegate { label7.Text = sitesToCrawl.Count.ToString(); }));
                this.Invoke(new MethodInvoker(delegate { label3.Text = currentCrawlingSite.Count().ToString(); }));



                if (levels == 0)
                {
                    return csFiles;
                }
                else
                {


                    for (int i = 0; i < webSites.Count(); i++)//&& i < 20; i++)                     {
                        int mx = Math.Min(webSites.Count(), 20); 


                            string t = webSites[i];
                            if ((t.StartsWith("http://") == true) || (t.StartsWith("https://") == true)) 
                            {

                                csFiles.AddRange(test(t, levels - 1, eve));
                            }

                    }
                    return csFiles;
                }



            }
            catch
            {
                return csFiles;
            }

        }

以及后台工作者 DoWork 和 ProgressReport 事件：

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {

                this.Invoke(new MethodInvoker(delegate { label2.Text = "Website To Crawl: "; }));
                this.Invoke(new MethodInvoker(delegate { label4.Text = mainUrl; }));
                test(mainUrl, levelsToCrawl, e);


        }

private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {


        }
4

1 回答 1

2

看起来您的表单正在被处置，然后您的 BackgroundWorker 正在尝试更新属于已处置表单的控件。

您可以处理表单的FormClosing事件并停止工作人员，或等待它完成。

或者，您的 BackgroundWorker 可以IsDisposed在尝试写出状态之前检查表单的属性。

但实际上，您应该使用ReportProgress, 而不是Invoke- 这也可以避免该问题。

于 2012-09-18T05:37:11.750 回答