[ Deserialize multiple row with DataContractJsonSerializer class ]

I've an API that return this:

{
"CODE": 200,
"EXAMS_LIST": {
    "0": {
        "CFU": " 9",
        "RESULT": "SOSTENUTO",
        "SSD": " MAT/05",
        "TAF": " A",
        "TEACHING": "MATEMATICA I CFU 9",
        "YEAR": 1
    },
    "1": {
        "CFU": " 4",
        "RESULT": "Sufficiente",
        "SSD": " L-LIN/12",
        "TAF": " E",
        "TEACHING": "LINGUA INGLESE (COLLOQUIO)",
        "YEAR": 1
    },
    "2": {
        "CFU": " 6",
        "RESULT": "SOSTENUTO",
        "SSD": " FIS/01",
        "TAF": " A",
        "TEACHING": "FISICA CFU 6",
        "YEAR": 1
    },
    ...........
    "22": {
        "CFU": " 5",
        "RESULT": " ",
        "SSD": "  ",
        "TAF": " E",
        "TEACHING": "PROVA FINALE CFU 5",
        "YEAR": 3
    }
}

I'm trying to parse it whit DataContractJsonSerializer class... i've maked support class in this way:

[DataContract]
public class Exam
{
    [DataMember(Name = "CFU", IsRequired = true)]
    private string cfu;
    [DataMember(Name = "RESULT", IsRequired = true)]
    private string result;
    [DataMember(Name = "SSD")]
    private string ssd;
    [DataMember(Name = "TAF")]
    private string taf;
    [DataMember(Name = "TEACHING", IsRequired = true)]
    private string teaching;
    [DataMember(Name = "YEAR", IsRequired = true)]
    private string year;

    public string Cfu
    {
        get { return cfu; }
        set { cfu = value; }
    }
    .........
    public string Year
    {
        get { return year; }
        set { year = value; }
    }
}}


[DataContract]
public class StudyPlanResponse
{
    [DataMember(Name="CODE")]
    public string Code {get;set;}
    [DataMember(Name = "EXAMS_LIST")]
    public ExamList Exams { get; set; }


}

[DataContract]
public class ExamList
{

    [DataMember(Name = "0")]
    public Exam ex0 { get; set; }
    [DataMember(Name = "1")]
    public Exam ex1 { get; set; }
    ............
    [DataMember(Name = "30")]
    public Exam ex30 { get; set; }

}

If I use List it doesn't work... and in this way, parsing is very slow... is there any solution? thanks in advance

Answer 1

---

In your response object EXAMS_LIST should be defined as Dictionary<int, Exam>. The problem is that DataContractJsonSerializer can not handle dictionaries properly. Your best bet is to use JSON.NET from Newtonsoft. Here is how you'd do it with JSON.NET:

Change EXAMS_LIST to Dictionary<int, Exam>

[DataContract]
public class StudyPlanResponse
{
    [DataMember(Name = "CODE")]
    public string Code { get; set; }            
    [DataMember(Name = "EXAMS_LIST")]
    public Dictionary<int, Exam> Exams { get; set; }
}

Call JSON.NET

StudyPlanResponse response = JsonConvert.DeserializeObject<StudyPlanResponse>(File.ReadAllText("TextFile1.json"));

Answer 2

---

The source uses a format that is compatible with a Dictionary rather than the more common List or Array, so the short answer is to use a Dictionary to deserialize the EXAMS_LIST element.

Two answers, both using the following structure:

public class StudyPlanResponse
{
    public int CODE { get; set; }
    public Dictionary<int, Exam> EXAMS_LIST { get; set; }

    public class Exam
    {
        public string CFU { get; set; }
        public string RESULT { get; set; }
        public string SSD { get; set; }
        public string TAF { get; set; }
        public string TEACHING { get; set; }
        public int YEAR { get; set; }
    }
}

First, using JSON.Net:

StudyPlanResponse studyplan = JsonConvert.DeserializeObject<StudyPlanResponse>(jsrc);

Second, using DataContractJsonSerializer:

var settings = new DataContractJsonSerializerSettings();
settings.UseSimpleDictionaryFormat = true;

DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(StudyPlanResponse), settings);
StudyPlanResponse studyplan;
using (var stream = new System.IO.MemoryStream(Encoding.UTF8.GetBytes(jsrc)))
{
    studyplan = (StudyPlanResponse)ser.ReadObject(stream);
}

I prefer the JSON.Net version, personally. The DataContractJsonSerializer version works, once you tell it to use the simple dictionary format via the settings object.