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POHow to remove Application.DoEvents() with better solution like BackgroundWorker in multithreading
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  1. POHow to remove Application.DoEvents() with better solution like BackgroundWorker in multithreading
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    copied!<p>This is my code. I am using Application.DoEvents() for waiting that UI thread is finished.</p> <pre><code>public override void Process(Crawler crawler, PropertyBag propertyBag) { AspectF.Define. NotNull(crawler, "crawler"). NotNull(propertyBag, "propertyBag"); if (propertyBag.StatusCode != HttpStatusCode.OK) return; if (!IsHtmlContent(propertyBag.ContentType)) return; m_Logger.Verbose("CefGlue started for url {0}", propertyBag.ResponseUri.ToString()); CefGlueBrowserForm cefGlueBrowserForm = new CefGlueBrowserForm(propertyBag.ResponseUri.ToString()); cefGlueBrowserForm.Show(); while (!cefGlueBrowserForm.Done) Application.DoEvents(); string htmlSource = cefGlueBrowserForm.DocumentDomHtml; propertyBag.GetResponse = () =&gt; new MemoryStream(Encoding.UTF8.GetBytes(htmlSource)); base.Process(crawler, propertyBag); } </code></pre> <p>I am reading that <code>Application.DoEvents()</code> is evil. I am also getting sometimes stackoverflow exception. What to use instead of <code>Application.DoEvents()</code>?</p> <p>I try something with <code>BackgroundWorker</code> but nothing works</p> <p>Example:</p> <pre><code>AutoResetEvent waitHandle = new AutoResetEvent(false); BackgroundWorker bw = new BackgroundWorker(); bw.WorkerReportsProgress = true; bw.WorkerSupportsCancellation = true; bw.DoWork += (sender, e) =&gt; { if (!e.Cancel) { CefGlueBrowserForm cefGlueBrowserForm = new CefGlueBrowserForm(propertyBag.ResponseUri.ToString()); cefGlueBrowserForm.Show(); while (!cefGlueBrowserForm.Done) Application.DoEvents(); e.Result = cefGlueBrowserForm.DocumentDomHtml; cefGlueBrowserForm.Dispose(); waitHandle.Set(); } }; bw.RunWorkerCompleted += (sender, e) =&gt; { string htmlSource = e.Result.ToString(); propertyBag.GetResponse = () =&gt; new MemoryStream(Encoding.UTF8.GetBytes(htmlSource)); base.Process(crawler, propertyBag); }; bw.RunWorkerAsync(TimeSpan.FromSeconds(10)); waitHandle.WaitOne(TimeSpan.FromSeconds(20)); </code></pre> <p>What can I do?</p> <p>EDIT:</p> <p>added code how cefGlueBrowserForm.Done is set.</p> <pre><code> public partial class CefGlueBrowserForm : Form { public CefGlueBrowserForm(string url) { m_Logger = NCrawlerModule.Container.Resolve&lt;ILog&gt;(); m_url = url; InitializeComponent(); CefManager.InitializeCef(); AddWebBrowser(m_url); } private void AddWebBrowser(string startUrl) { m_textBox = new TextBox { Dock = DockStyle.Bottom, ReadOnly = true, }; m_textBox.Parent = this; Console.Box = m_textBox; Console.WriteLine("Loading URL ..."); CefGlueBrowser = new ChromiumCefWebBrowser(); CefGlueBrowser.Dock = DockStyle.Fill; CefGlueBrowser.BringToFront(); CefGlueBrowser.StartUrl = startUrl; CefGlueBrowser.Parent = this; Controls.Add(CefGlueBrowser); Console.WriteLine("URL " + startUrl + " loaded."); CefGlueBrowser.LoadEnd += Browser_LoadEnd; } private void Browser_LoadEnd(object sender, EventArgs e) { m_Logger.Verbose("Page load was ended for url {0}", m_url); MyCefStringVisitor visitor = new MyCefStringVisitor(this, m_url); ((LoadEndEventArgs)e).Frame.Browser.GetMainFrame().GetSource(visitor); } private class MyCefStringVisitor : CefStringVisitor { #region Instance Fields private CefGlueBrowserForm m_cefGlueBrowserForm; private string m_url; private ILog m_Logger; #endregion #region Constructors public MyCefStringVisitor(CefGlueBrowserForm cefGlueBrowserForm, string url) { m_Logger = NCrawlerModule.Container.Resolve&lt;ILog&gt;(); m_cefGlueBrowserForm = cefGlueBrowserForm; m_url = url.NormalizeUrl(); } #endregion #region Instance Methods protected override void Visit(string value) { string currentUrl = m_cefGlueBrowserForm.CefGlueBrowser.Browser.GetMainFrame().Url.NormalizeUrl(); if (m_url.Equals(currentUrl, StringComparison.OrdinalIgnoreCase) || currentUrl.Contains(m_url)) { m_Logger.Verbose("Getting html source for url {0} and closing Event", m_url); m_cefGlueBrowserForm.DocumentDomHtml = value; m_cefGlueBrowserForm.Done = true; m_cefGlueBrowserForm.CefGlueBrowser.LoadEnd -= m_cefGlueBrowserForm.Browser_LoadEnd; } } #endregion } #endregion } </code></pre>
 

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