CODEWITHSUNDEEP
c#json.netgeneric-collections
Pete Hesse
Pete Hesse

Reputation: 45

c# JSONConvert.DeserializeObject<List<RootObject>> returns nulls

I am trying to deserialize an HTTPWebRequest response (Json) to a c# object/class, but am having trouble. A collection with 10 instances of the object are returned, and all the objects are null.

Here is the json:

[
{
"id":2227,
"user_id":441,
"grades":
    {"html_url":"https://...",
    "current_score":91.26,
    "current_grade":null,
    },
"sis_account_id":"11",
"user":
    {"id":441,
     "name":"Nicholas Bailey",
    }
},

Here are the classes:

    public class Grade
{
    public string html_url { get; set; }
    public decimal current_score { get; set; }
    public string current_grade { get; set; }
}
public class User
{
    public int id { get; set; }
    public string name { get; set; }
}
public class Enrollment
{
    public int id { get; set; }
    public int user_id { get; set; }
    public Grade grades { get; set; }
    public string sis_account_id { get; set; }
    public User user { get; set; }
}
public class RootObject
{
    public Enrollment enrollment { get; set; }
}

And here is my code:

  HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://(some uri)");

        WebResponse response = request.GetResponse();

        StreamReader sr = new StreamReader(response.GetResponseStream());

        string content = sr.ReadToEnd();

        JsonSerializerSettings settings = new JsonSerializerSettings();
        settings.MetadataPropertyHandling = MetadataPropertyHandling.Ignore;

        var outObject = JsonConvert.DeserializeObject<List<RootObject>>(content, settings);

I have been looking at a lot of code on google but have not found a situation that is close to mine. Also, I'm a bit green on generic collections. The code runs fine but in the debugger the "outObject" contains 10 entries, each with an "Enrollment" object that is null.

I also have tried this with json that has well over 10 entries, but it still comes up with 10. But I'm more focused on the nulls at this point (One thing at a time!). For the sake of brevity I have removed several entries in the json, but the main pattern (an enrollment object with a grades object and a user object embedded in it) remains.

Any help would be much appreciated. Thanks.

Upvotes: 1

Views: 8872

Answers (1)

dbc
dbc

Reputation: 117275

Deserialize to List<Enrollment> not List<RootObject>: 

var enrollment = JsonConvert.DeserializeObject<List<Enrollment>>(content, settings);

The first JSON object in the root array has properties "id", "user_id" and so on that correspond to the members of Enrollment. Conversely there is no property "enrollment" in the JSON anywhere.

Sample fiddle.

Update

You asked, I tried this and now I'm getting an exception "Error converting value {null} to type 'System.Int32'. Path '[0].associated_user_id', line 1, position 165." associated_user_id was removed for brevity but I will add it back into my code. Any ideas?

Somewhere your data model you must have the following member (field or property):

public int associated_user_id;

Change this to a nullable:

public int? associated_user_id;

Upvotes: 2

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