How do I can use webBrowser with asp.net?

Question

My code is as following:

 protected void Page_Load(object sender, EventArgs e)
    {

        webBrowser1 = new WebBrowser();

        webBrowser1.Navigate("http://www.wine-searcher.com/wine-valuation-f.lml");


        webBrowser1.DocumentCompleted += new WebBrowserDocumentCompletedEventHandler(webBrowser1_DocumentCompleted);


    }



    private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
    {

        webBrowser1.Document.GetElementById("wn1_input").InnerText = "William Fevre Les Clos, Chablis Grand Cru, France";
        webBrowser1.Document.GetElementById("vt1_input").InnerText = "NV";
        webBrowser1.Document.GetElementById("valButton").InvokeMember("click");
        TextBox1.Text= webBrowser1.Document.GetElementById("value1").InnerHtml;
    }

when I debug I get the nullreferenceException about my first line:

webBrowser1.Document.GetElementById("wn1_input").InnerText = "William Fevre Les Clos, Chablis Grand Cru, France";

How can I resolve this please ?

Try assigning webBrowser1.DocumentCompleted handler before navigating? — Yuriy Galanter, Jun 05 '14 at 14:12
@yurly, if that was the problem, webbrowser1_DocumentCompleted would never get called. — Aheho, Jun 05 '14 at 14:20
it's still raising null exception , It worked for me using windows form application with the same code,that's weird ! maybe because I added to my page:AutoEventWireup="true" and to my web conf : — user3711521, Jun 05 '14 at 14:23
Are you really trying to load a web browser control (Which afaik is mainly intended for WinForms apps?) on your server then browse to a page and I assume try to get some javascript onclick event to run and give you a result? If so, there has got to be a better way! — Richard Dalton, Jun 05 '14 at 15:17

score 1 · Answer 1 · answered Jun 05 '14 at 14:19

1

You should not use the WebBrowser control on .NET. If you want to grab an Html page you have many options, like the WebClient class:

http://msdn.microsoft.com/en-us/library/fhd1f0sw(v=vs.110).aspx

http://msdn.microsoft.com/en-us/library/ms144202(v=vs.110).aspx

or HttpClient

http://msdn.microsoft.com/it-it/library/system.net.http.httpclient.aspx

to grab contents on an html document, you could give a try at a porting of the HtmlTidy library, such as http://sourceforge.net/projects/tidynet/

answered Jun 05 '14 at 14:19

pomarc

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On second thought, I would probably go with one of pomarc's recommendations. – TrevorBrooks Jun 05 '14 at 14:40
@user3711521 you can use, in alternative, the easier htmlagility pack, as in http://stackoverflow.com/questions/2113924/how-can-i-use-html-agility-pack-to-retrieve-all-the-images-from-a-website – pomarc Jun 12 '14 at 20:55

How do I can use webBrowser with asp.net?

1 Answers1