将可移植类库与Webrequest和WP8一起使用

Question

I have a problem to which I can't find any solution, and I find it hard to believe I'm the only one getting this error.

I have this piece of C# code in a Portable Class Library

static public void GetAnimeListFromWeb(ObservableCollection<AnimeViewModel> collection, string Url, string encodedLogin = "")
    {
        WebRequest request = WebRequest.Create(Url);
        request.Headers["Authorization"] = encodedLogin;

        IAsyncResult asyncResult = request.BeginGetResponse(new AsyncCallback( s => {
            WebResponse response = (s.AsyncState as WebRequest).EndGetResponse(s);
            XDocument doc = XDocument.Load(response.GetResponseStream());

            IEnumerable<AnimeViewModel> result = ParseAnimeXML(doc);

            collection = (ObservableCollection<AnimeViewModel>)result;

        }), request);
    }

When I compile this, it builds, and the code also works in a small console program I wrote to test it. However, when testing in a Windows Phone 8 app it crashes on

WebResponse response = (s.AsyncState as WebRequest).EndGetResponse(s);

It throws an ArgumentException. When I inspected the 's' variable, it said the AsyncWaitHandle gave a NotSupportedException.

My question is then, how can I make a proper Webrequest that would work on all platforms?

EDIT: Maybe it is useful to note that I'm targeting .NET 4.5, SL4 and higher, WP7 and higher and .NET for Windows Store Apps

Answer 1

In my opinion, you'll need to use latest Asyc/Await concept to perform this task like DownloadStringAsync. Because Async/Await is the only supported mechanism in Windows 8 and Windows Phone 8. However, when you use this code and build it for multiple platforms, compiler will handle the intricacies of different platform and produce the required code.