DownloadStringAsync() does not download the string asynchronously

Question

Trying to implement downloadStringAsync() to prevent UI freezing for 10 seconds when downloading one byte of data. However, even though the download completes, it is freezing the UI just as if I used downloadString().

Here is my code:

    public void loadHTML()
    {
            WebClient client = new WebClient();

            // Specify that the DownloadStringCallback2 method gets called
            // when the download completes.
            client.DownloadStringCompleted += new DownloadStringCompletedEventHandler(loadHTMLCallback);
            client.DownloadStringAsync(new Uri("http://www.example.com"));
            return;
    }

    public void loadHTMLCallback(Object sender, DownloadStringCompletedEventArgs e)
    {
        // If the request was not canceled and did not throw
        // an exception, display the resource.
        if (!e.Cancelled && e.Error == null)
        {
            string result = (string)e.Result;

            // Do cool stuff with result

        }
    }

Answer 1

Encountered the same problem, and found a solution. Quite complex discussion here: http://social.msdn.microsoft.com/Forums/en-US/a00dba00-5432-450b-9904-9d343c11888d/webclient-downloadstringasync-freeze-my-ui?forum=ncl

In short, the problem is web client is searching for proxy servers and hanging the app. The following solution helps:

WebClient webClient = new WebClient();
webClient.Proxy = null;
... Do whatever else ...