In this example I've created a Web Scraper using WebBrowser control.
It runs the WebBrowser control in a background thread and returns Task<string>. The usage is easy:
var content = await WebScraper.BrowserBasedWebScraper.LoadUrl("http://www.example.com");
You can use it in Web and Windows Application. I've added an example for ASP.NET MVC project and another one for Windows Forms project.
The reason of using a WebBrowser control instead of WebClient or HttpClient is, using WebBrowser control, you can add a delay after loading the content of WebBrowser control to let the broswer render the site and run scripts after document got ready, then get the content from DocumentText property of the WebBrowser control. However the delay is not included in example and you can simply add delay yourself.