Why am I being thrown a NullReferenceException when I try to find an element?

Question

I am currently working on a bo that goes in a search bar, selects an element, and gets its href link. I am using the following code and I got NullReferenceExceptions thrown. Does anyone know why?

    webBrowser1.Navigate("https://us.octobersveryown.com/search?q=shirt");
    Thread.Sleep(1000);
    String test = webBrowser1.Document.GetElementsByTagName("body")[0].GetAttribute("class");

Thanks, Nickolas

Quite probably `webBrowser1.Document.GetElementsByTagName("body")[0]` is null. Try to debug your program to verify this. — Christos, Feb 18 '17 at 07:07
An unhandled exception of type 'System.NullReferenceException' occurred in BlarBot.exe Additional information: Object reference not set to an instance of an object. — Blar321, Feb 18 '17 at 07:08

score 0 · Accepted Answer · answered Feb 18 '17 at 07:21

You should put that under DocumentCompleted event and access the document in your handle when it fires:

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
    {
        string test = webBrowser1.Document.GetElementsByTagName("body")[0].GetAttribute("class");
    }

Your navigation is not yet loading even though you call the Navigate method. That's why it returns null.

Why am I being thrown a NullReferenceException when I try to find an element?

1 Answers1