CODEWITHSUNDEEP
c#
Vincent Dagpin
Vincent Dagpin

Reputation: 3611

C# NullReferenceException on GetElementById HtmlElement

this is inside my sample.html

<html>
    <head>
        <title>Test</title>    
    </head>
    <body>
        <div id="testingID">hello</div>
    </body>
</html>

and i have this code in c# that i want to prompt is the world "hello" inside the div element with the id testingID

private void btnGetData_Click(object sender, EventArgs e)
    {
        string url = string.Format("{0}/sample.html", Environment.CurrentDirectory);
        WebBrowser webb = new WebBrowser();

        webb.Navigate(url);

        var doc = webb.Document;
        HtmlElement elem = doc.GetElementById("testingID");
        MessageBox.Show(elem.InnerText);
    }

but i get Object reference not set to an instance of an object. on MessageBox.Show(elem.InnerText);

a little help here..

Upvotes: 1

Views: 2195

Answers (2)

rybosome
rybosome

Reputation: 5136

I'm assuming that elem is null because an element with an ID of 'testingID' is not being found in the document. Try stepping through with a debugger and verifying that elem is not null. Alternatively, try something like the following:

if (elem != null)
{
    MessageBox.Show(elem.InnerText);
}
else
{
    MessageBox.Show('No element found!');
}

Upvotes: 1

Davita
Davita

Reputation: 9124

Probably, you are trying to access the element, but the document is not loaded at the moment. Move doc.GetElementById("testingID"); in WebBrowser.DocumentCompleted event and it should work.

Upvotes: 5

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