如何处理来自httpclient的数据

我正在开发一个新的Windows Phone 8应用程序。我正在连接到返回有效json数据的Web服务。我正在使用longlistselector来显示数据。当我在GetAccountList（）中使用字符串json时，此方法工作正常；但是从DataServices类接收数据时，出现错误“无法将类型'System.Threading.Tasks.Task'隐式转换为字符串”。不知道出了什么问题。欢迎任何帮助。谢谢！

DataServices.cs

    public async static Task<string> GetRequest(string url)
    {
        HttpClient httpClient = new HttpClient();

        await Task.Delay(250);

        HttpResponseMessage response = await httpClient.GetAsync(url);
        response.EnsureSuccessStatusCode();
        string responseBody = await response.Content.ReadAsStringAsync();
        Debug.WriteLine(responseBody);
        return await Task.Run(() => responseBody);
    }

AccountViewModel.cs

 public static List<AccountModel> GetAccountList()
    {
        string json = DataService.GetRequest(url);
        //string json = @"{'accounts': [{'id': 1,'created': '2013-10-03T16:17:13+0200','name': 'account1 - test'},{'id': 2,'created': '2013-10-03T16:18:08+0200','name': 'account2'},{'id': 3,'created': '2013-10-04T13:23:23+0200','name': 'account3'}]}";
        List<AccountModel> accountList = new List<AccountModel>();

        var deserialized = JsonConvert.DeserializeObject<IDictionary<string, JArray>>(json);

        JArray recordList = deserialized["accounts"];


        foreach (JObject record in recordList)
        {
            accountList.Add(new AccountModel(record["name"].ToString(), record["id"].ToString()));
        }

        return accountList;
    }

更新：我稍作更改，现在就像一个魅力。谢谢你的帮助！DataServices.cs

     //GET REQUEST
    public async static Task<string> GetAsync(string url)
    {
        var httpClient = new HttpClient();

        var response = await httpClient.GetAsync(url);

        string content = await response.Content.ReadAsStringAsync();

        return content;
    }

AccountViewModel.cs

    public async void LoadData()
    {
        this.Json = await DataService.GetAsync(url);
        this.Accounts = GetAccounts(Json);
        this.AccountList = GetAccountList(Accounts);
        this.IsDataLoaded = true;
    }

    public static IList<AccountModel> GetAccounts(string json)
    {
        dynamic context = JObject.Parse(json);

        JArray deserialized = (JArray)JsonConvert.DeserializeObject(context.results.ToString());

        IList<AccountModel> accounts = deserialized.ToObject<IList<AccountModel>>();

        return accounts;
    }

    public static List<AlphaKeyGroup<AccountModel>> GetAccountList(IList<AccountModel> Accounts)
    {
        List<AlphaKeyGroup<AccountModel>> accountList = AlphaKeyGroup<AccountModel>.CreateGroups(Accounts,
                System.Threading.Thread.CurrentThread.CurrentUICulture,
                (AccountModel s) => { return s.Name; }, true);

        return accountList;
    }