WebBrowser Document Completed Event C#

Question

Below is the function I use as my browsers\' DocumentCompleted event, and also the navBtnClick() method which is responsible for creating the web b

Answer 1

For me, http://www.google.com redirects to http://www.google.ca. If something similar happens for you, they you may be getting a document completed event for each of those two documents. Try outputting/tracing WebBrowserDocumentCompletedEventArgs.Url to see what document was completed.

Answer 2

As I recall, DocumentCompleted will fire multiple times if the document being navigated to has iframes that embed other web pages.

If you only want to receive the event exactly once, just unsubscribe from the DocumentCompleted handler:

public void WebBrowser_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e) 
{
   var webBrowser = sender as WebBrowser;
   webBrowser.DocumentCompleted -= WebBrowser_DocumentCompleted;
   MessageBox.Show(webBrowser.Url.ToString() );
}    

private void navBtnClick(object sender, EventArgs e)
{
     var wbrowser = new WebBrowser();
     wbrowser.DocumentCompleted +=new WebBrowserDocumentCompletedEventHandler(WebBrowser_DocumentCompleted);
     wbrowser.Navigate("http://www.google.com");
}

---

Alternately, you can use System.IObservable and ReactiveExtensions to subscribe to exactly one event firing:

private void navBtnClick(object sender, EventArgs e)
{
     var browser = new WebBrowser();
     var docCompleted = Observable.FromEventPattern<WebBrowserDocumentCompletedEventArgs>(browser, "DocumentCompleted")
     docCompleted
         .Take(1) // Take only one event firing
         .Subscribe(i => MessageBox.Show(browser.Url.ToString()));

     browser.Navigate("http://www.google.com");
}