Error get data in webbrowser

Question

have a form and one webbrowser now I want to retrieve data displayed on the webbrowser must do? Div Tags:

<div id="divTop">

    <div id="text-conent" style="width: 500px; float: right;"></div>
    <div id="grid" style="margin-removed 505px; height: 700px;"></div>

</div>

Code get data from webbrowser:

HtmlAgilityPack.HtmlDocument doc = (HtmlAgilityPack.HtmlDocument)webBrowser1.Document.DomDocument;
string texts = doc.DocumentNode.SelectSingleNode("//div[@class='text-conent']/p]").InnerText;
richTextBox1.Text = texts;

Error:

Unable to cast COM object of type 'mshtml.HTMLDocumentClass' to class type 'HtmlAgilityPack.HtmlDocument'. Instances of types that represent COM components cannot be cast to types that do not represent COM components; however they can be cast to interfaces as long as the underlying COM component supports QueryInterface calls for the IID

I have to how to get the data in the correct webbrowser