I found a good Code Snippet for Downloading Youtube Files with C# .net.
http://sourcecodecenter.blogspot.com/2011/05/download-youtube-videos-with-c.html
I also tried this code on Windows Phone but the classes HtmlAgilityPack, HtmlDocument and HtmlNode aren’t there. Anyway:
WebRequest request = WebRequest.Create(url);
WebResponse response = request.GetResponse();
isn’t working. There aren’t a lot of lines not working as you can see…
I don’t know the right windows phone classes for that.
HtmlAgilityPack – To use this on Windows Phone 7, you need to check out the folder named HAPPhone or HAPPhone7.1 from CodePlex and then build it your self
WebRequest – In silverlight, you need to get the response asynchronously. An example can be found here: http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest(VS.95).aspx