在Windows Phone 8.1中读取在线JSON数据

Question

I am developing a hub-pivot app for windows phone 8.1. I am accessing the sampledata.json available in Datamodel folder. But how to use the same sampledata.json file online.

The file is accessible by using

        Uri dataUri = new Uri("ms-appx:///DataModel/SampleData.json");

and data is getting parse by using

        StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(dataUri);
        string jsonText = await FileIO.ReadTextAsync(file);
        JsonObject jsonObject = JsonObject.Parse(jsonText);
        JsonArray jsonArray = jsonObject["Groups"].GetArray();

        foreach (JsonValue groupValue in jsonArray)
        {
            JsonObject groupObject = groupValue.GetObject();
            SampleDataGroup group = new SampleDataGroup(groupObject["UniqueId"].GetString(),
                                                        groupObject["Title"].GetString(),
                                                        groupObject["Subtitle"].GetString(),
                                                        groupObject["ImagePath"].GetString(),
                                                        groupObject["Description"].GetString());

            foreach (JsonValue itemValue in groupObject["Items"].GetArray())
            {
                JsonObject itemObject = itemValue.GetObject();
                group.Items.Add(new SampleDataItem(itemObject["UniqueId"].GetString(),
                                                   itemObject["Title"].GetString(),
                                                   itemObject["Subtitle"].GetString(),
                                                   itemObject["ImagePath"].GetString(),
                                                   itemObject["Description"].GetString(),
                                                   itemObject["Content"].GetString()));
            }
            this.Groups.Add(group);
        }

I want to do httprequest, and I had also tried

        var client = new HttpClient();
        HttpResponseMessage response = await client.GetAsync(new Uri("http://url/sampledata.json"));
        string jsonString = await response.Content.ReadAsStringAsync();

After this I am struck. Please Help

Answer 1

I have some helper methods to autoconvert JSON to required type. My ASP.NET WebAPI service returns JSON and I'm posting data also in JSON format.

public static async Task<TRes> Post<TReq, TRes>(string url, TReq data, HttpClient httpClient)
{
    HttpContent content = ToJsonHttpContent(data);
    HttpResponseMessage response = await httpClient.PostAsync(url, content);
    response.EnsureSuccessStatusCode();
    return await response.Content.Extract<TRes>();
}

public static async Task<T> Extract<T>(this HttpContent me)
{
    DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(T));
    using (Stream stream = await me.ReadAsStreamAsync())
    {
        return (T)serializer.ReadObject(stream);
    }
}

public static HttpContent ToJsonHttpContent(object data)
{
    string jsonData = JsonConvert.SerializeObject(data);
    return new StringContent(jsonData, Encoding.UTF8, "application/json");
}