WebClient.DownloadString() Not Producing Exact HTML

So here's the deal. I'm creating a spider bot for a website that scans all the product pages and records the product data. I'm using C# and the WebClient library to download the HTML string. The site I'm crawling must be specially made because the HTML that is received from开发者_运维百科 WebClient.DownloadString() is different than the HTML that I get when I view the source of the HTML when visiting it on a browser. This seems intentional because the only info I can't get is the price.

Does anyone know a workaround for this problem or can anyone explain what is happening? Thanks.

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It is probably using the the user agent string to decide what content to send. The example here shows how to set the user agent header.