(AsyncWebClient) Async Webclient for windows phone 8

Using windows phone web client is pretty common but the thing is you can not use it using Async -> Await mechanism so i used threading to create an async functionality for The Download string and upload string methods here is the code below

// Comment
 public class AsyncWebClient
    {
        public Task DownloadString(Uri uri)
        {
            var task = new TaskCompletionSource();

            try
            {
                var client = new WebClient();
                client.DownloadStringCompleted += (s, e) =>
                {
                   task.SetResult(e.Result);
                };

                client.DownloadStringAsync(uri);
            }
            catch (Exception ex)
            {
                task.SetException(ex);
            }

            return task.Task;
        }

        public Task UploadString(Uri uri, string content)
        {
            var task = new TaskCompletionSource();

            try
            {
                var client = new WebClient();
                client.UploadStringCompleted += (s, e) =>
                {
                    task.SetResult(e.Result);
                };

                client.UploadStringAsync(uri,content);
            }
            catch (Exception ex)
            {
                task.SetException(ex);
            }

            return task.Task;
        }
    }