Deserialize Json to Class that implements Ienumerable in Asp.net

Question

I've below function which fetches facebook data and return it as string.

public static string GetUserNewsFeed(string strAccessToken)
{
    Dictionary<string, object> PostDetail = new Dictionary<string, object>();
    DateTime CreatedDateTime = DateTime.Today.AddDays(-90);
    var epoch = (CreatedDateTime.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
    PostDetail.Add("Posts", "SELECT post_id,source_id FROM stream WHERE filter_key in (SELECT filter_key FROM stream_filter WHERE uid=me() AND type='newsfeed') and (likes.count > 0 or comments.count > 0) and created_time > " + epoch);
    PostDetail.Add("PostComments", "select post_id,fromid from comment where post_id in (select post_id from #Posts)");
    PostDetail.Add("PostLikes", "SELECT object_id,post_id,user_id FROM like WHERE post_id in (select post_id from #Posts)");
    string Json = HttpUtility.UrlEncode(Newtonsoft.Json.JsonConvert.SerializeObject(PostDetail));       
    return RunFQLQuery(Json, strAccessToken);
}

Here's the code that calls this function and convert it to Jobject using Json.NET :

strFeed = FacebookAPI.GetUserNewsFeed(Convert.ToString(Session["access_token"]));
JObject objStreamData = JObject.Parse(strFeed);
var PostResponse = objStreamData.SelectToken("data[0]");

Below line deserialize it to NewsFeedPost Class :

var Posts = JsonConvert.DeserializeObject<NewsFeedPost>(PostResponse.ToString());

And below is the class :

public class NewsFeedPost 
{      
    public string name { get; set; }
    public List<Post> fql_result_set { get; set; }
}
public class Post
{
    public string post_id { get; set; }
    public string source_id { get; set; }
}

Now problem is when I change my NewsFeedPost class to below it throws error "Cannot deserialize JSON object into type 'BAL.NewsFeedPost'" :

public class NewsFeedPost : IEnumerable<Post>
{      
    public string name { get; set; }
    public List<Post> fql_result_set { get; set; }
    public IEnumerator<Post> GetEnumerator()
    {
        foreach (Post item in fql_result_set)
        {
            yield return item;
        }
    }
    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }

}

Below is the sample of Json Response :

{
  "data": [
{
  "name": "Posts",
  "fql_result_set": [
    {
      "post_id": "1"
    },
    {
      "post_id": "2"
    }
  ]
},
{
  "name": "PostComments",
  "fql_result_set": [
    {
      "post_id": "3",
      "fromid": 4
    },
    {
      "post_id": "5",
      "fromid": 6
    }
  ]
},
{
  "name": "PostLikes",
  "fql_result_set": [
    {
      "object_id": 7,
      "post_id": "8",
      "user_id": 9
    },
    {
      "object_id": 10,
      "post_id": "11",
      "user_id": 12
    }
  ]
}
]
}

I just want to enumerate through list and create comma delimited list and save it to db. Can anybody throw some light what needs to be done? How can I get the Count and Length Property for List?

Can you post an example of the JSON that you are trying to deserialize? — Dave Walker, Feb 09 '12 at 14:01

score 5 · Accepted Answer · answered Feb 09 '12 at 15:59

5

Two things:

1) Add JsonObjectAttribute to NewsFeedPost:

[JsonObject]
public class NewsFeedPost : IEnumerable<Post>

2) To deserialize that JSON which you show, you need another class:

public class NewsFeedPosts
{
    public List<NewsFeedPost> Data { get; set; }
}

and then you'd call your deseralize with that class as what you want deserialized:

var Posts = JsonConvert.DeserializeObject<NewsFeedPosts>(PostResponse.ToString());

answered Feb 09 '12 at 15:59

Jesse C. Slicer

19,901
3
68
87

Just decorating my class with JsonObject attribute does the trick, and didn't have to declare one more class. Thanks a lot. I really appreciate. – user686021 Feb 10 '12 at 05:10

score 0 · Answer 2 · answered Feb 09 '12 at 16:01

0

You may want to try a cast on the DeserializeObject

var Posts = JsonConvert.DeserializeObject<NewsFeedPost>((NewsFeedPost)PostResponse.ToString());

answered Feb 09 '12 at 16:01

Orin

351
5
13

Do you cast String to NewsFeedPost? It's wrong code. – Mark Khromov Sep 30 '17 at 17:27

Deserialize Json to Class that implements Ienumerable in Asp.net

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