I want to parse from a JSON file in a universal windows phone application but I can't convert task to string 

```
public MainPage()
    {
        this.InitializeComponent();

        HttpClient httpClient = new HttpClient();
        String responseLine;
        JObject o;
        try
        {
            string responseBodyAsText;

            HttpResponseMessage response = httpClient.GetAsync("http://localhost/list.php").Result;

            //response = await client.PostAsync(url, new FormUrlEncodedContent(values));
            response.EnsureSuccessStatusCode();
            responseBodyAsText = response.Content.ReadAsStringAsync().Result;
           // responseLine = responseBodyAsText;
              string Website = "http://localhost/list.php";
            Task<string> datatask =  httpClient.GetStringAsync(new Uri(string.Format(Website, DateTime.UtcNow.Ticks)));
            string data = await datatask;
            o = JObject.Parse(data);
            Debug.WriteLine("firstname:" + o["id"][0]);
        }
        catch (HttpRequestException hre)
        {
        }

```

I have error in this line 

```
 string data = await datatask;

```

how can I fix it?