Question

I’m trying to download and parse a website using the async functions for a Windows 8 app.

I call the download code in this method:

private async Task<Show> getSeasonAndEpisodeInformation(Show currentShow)
    {
        int seriesID = currentShow.SeriesID;
        EpisodeBuilder epBuilder = new EpisodeBuilder(seriesID);

        List<Episode> eps = await epBuilder.getEpisodeList();
        SeasonBuilder seasonBuilder = new SeasonBuilder(eps);

        return currentShow;
    }

And the getEpisodeList() function is:

public async Task<List<Episode>> getEpisodeList()
    {
        httpClient = new HttpClient();
        httpClient.MaxResponseContentBufferSize = 2560000;
        httpClient.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; WOW64; Trident/6.0)");

        try
        {
            List<Episode> episodes = new List<Episode>();
            HttpResponseMessage response = await httpClient.GetAsync(new Uri("http://www.example.com"));
            response.EnsureSuccessStatusCode();
            //Never get here

            return episodesList;
        }
        catch (Exception)
        {

        }

        return null;
    }

If I have the getEpisodeList method be void then the webpage will download and continue. I have debugged and made sure that it is the httpClient.GetAsync(..) line that is never completing. Is there anyway around this?

In the getSeasonAndEpisodeInformation method, I need to make sure that the getEpisodeList() method has returned before continuing – hence the use of the await keyword when calling epBuilder.getEpisodeList().

Answer 1

I fixed this by removing the “await” keyword when I call http.GetAsync. The call now finishes and the ‘await’ in the getSeasonAndEpisodeInformation method ensures that it runs asynchronously.