Partial deserialization of JSON object by using DataContractJsonSerializer

c#, datacontractjsonserializer, datacontractserializer, deserialization, json

Solution

Your code doesn't work, because the JSON object you're deserializing doesn't have any of the `User` properties. The deserializer certainly won't try looking into children of the current object to see if something matches.

What you should do is to create a type that represents the whole response object. If you're not interested in the `repositories` part, then just omit it.

The following code works for me:

[DataContract]
public class BitbucketResponse
{
    [DataMember(Name="user")]
    public BitbucketUser User { get; set; }
}

[DataContract]
public class BitbucketUser
{
    [DataMember(Name = "username")]
    public string Username { get; set; }

    // etc.
}

…

var serializer = new DataContractJsonSerializer(typeof(BitbucketResponse));
using (var stream = …)
{
    var response = (BitbucketResponse)serializer.ReadObject(stream);
    var user = response.User;
}

Problem

As a response from a Bitbucket REST API I'm getting the following JSON object (simplified version): ``` { "repositories": [ { "scm": "hg", "has_wiki": false, "language": "c#", "slug": "Repo1" }, { "scm": "hg", "has_wiki": false, "language": "java", "slug": "Repo2" }, { "scm": "hg", "has_wiki": true, "language": "c#", "slug": "Repo3" } ], "user": { "username": "someuser", "first_name": "Some", "last_name": "User", "display_name": "Some User", "is_team": false, "avatar": "https://someuseravatar.com", "resource_uri": "/1.0/users/someuser" } } ``` The only part from this JSON object I need to be deserialized is a `user` part. For that purposes I created the following class: ``` [DataContract(Name="user")] public class BitbucketUser { [DataMember(Name = "username")] public string Username { get; set; } [DataMember(Name = "first_name")] public string FirstName { get; set; } [DataMember(Name = "last_name")] public string LastName { get; set; } [DataMember(Name = "display_name")] public string DisplayName { get; set; } [DataMember(Name = "is_team")] public bool IsTeam { get; set; } [DataMember(Name = "avatar")] public string Avatar { get; set; } [DataMember(Name = "resource_uri")] public string ResourceUri { get; set; } } ``` And a helper method to deserialize json: ``` public static T Deserialize<T>(string json) { DataContractJsonSerializer deserializer = new DataContractJsonSerializer(typeof(T)); using (MemoryStream stream = new MemoryStream(Encoding.Unicode.GetBytes(json))) { T result = (T)deserializer.ReadObject(stream); return result; } } ``` So, when I'm trying to get deserialized `User` object by using this code: ``` User user = JsonHelper.Deserialize<User>(jsonResponse); ``` Then I'm getting `user` object created containing all properties as `null`. I have tried to find right attributes to use on class header, but the result is same. And also I'm not using a Json.NET library just to avoid extra library reference as well as I'm not creating wrapper class to hold that user object as property of `User` type and repositores object as a array of the Repositories[] type. Is there a solution for this issue to get deserialized user object without null fields ?

Original source