Appending to JSON object using JSON.net

Question

I need to serialize a JSON object that looks like this:

{
   "Documents": [
      {
         "Title": "",
         "DatePublished": "",
         "DocumentURL": "",
         "ThumbnailURL": "",
         "Abstract": "",
         "Sector": "",
         "Country": [
            "", "", ""
         ],
         "Document Type": ""
      }
   ]
}

What I'm doing is taking the data from SQL server and storing the results into an object like this:

public List<Dictionary<string, string>> GetResults()
{
    int index = 0;
    while (this.myReader.Read())
    {

        this.dataFrmDb = new Dictionary<string, string>();
        for (int i = 0; i < myReader.FieldCount; i++)
        {
            if (myReader.GetName(i) == "Country")
            {
                string[] delimiter = { " _qfvcq_ " };
                string text = myReader[myReader.GetName(i)].ToString();
                string[] results = text.Split(delimiter, StringSplitOptions.None);

                //This list stores the values for "Country". 
                List<string> countries = new List<string>();
                for (int j = 0; j < results.Count(); j++)
                {
                    countries.Add(results[j].ToString()); 
                }
            }
            else
            {                           
                this.dataFrmDb.Add(myReader.GetName(i), 
                          myReader[myReader.GetName(i)].ToString());
            }
        }

        this.dictList.Add(this.dataFrmDb);
    }
    return this.dictList;
}

I then take this data and serialize like this:

Database connect = new Database(
    System.Configuration.ConfigurationManager.AppSettings["DatabaseConnectionString"],
    System.Configuration.ConfigurationManager.AppSettings["StoredProcedure"]);

List<Dictionary<string, string>> dataResults = connect.GetResults();           

Dictionary<string, List<Dictionary<string, string>>> myList = 
            new Dictionary<string, List<Dictionary<string, string>>>();

myList.Add("Documents", dataResults);

string ans = JsonConvert.SerializeObject(myList, Formatting.Indented);
System.Console.WriteLine(ans);

I get the proper output but if you would look in the original JSON format, "Country" needs to have multiple values. I don't know how to implement that into this JSON object. How do I add a list with the "Country" values to the JSON object using JSON.net? Is there another way to go about this?

Brian Rogers · Accepted Answer · 2013-04-10 00:59:58Z

If you change dataFrmDb to be Dictionary<string, object> instead of a Dictionary<string, string>, then you can store the Countries list into it like the other values. Json.Net will then serialize it like you want.

Here is an example program which demonstrates:

class Program
{
    static void Main(string[] args)
    {
        List<Dictionary<string, object>> dataResults = GetResults();           
        Dictionary<string, List<Dictionary<string, object>>> myList = 
                      new Dictionary<string, List<Dictionary<string, object>>>();
        myList.Add("Documents", dataResults);
        string ans = JsonConvert.SerializeObject(myList, Formatting.Indented);
        System.Console.WriteLine(ans); 
    }

    public static List<Dictionary<string, object>> GetResults()
    {
        List<Dictionary<string, object>> dictList = new List<Dictionary<string, object>>();

        Dictionary<string, object> dataFrmDb = new Dictionary<string, object>();
        dataFrmDb.Add("Title", "An Example Document");
        dataFrmDb.Add("DatePublished", DateTime.Now.ToString());
        dataFrmDb.Add("DocumentURL", "http://www.example.org/documents/1234");
        dataFrmDb.Add("ThumbnailURL", "http://www.example.org/thumbs/1234");
        dataFrmDb.Add("Abstract", "This is an example document.");
        dataFrmDb.Add("Sector", "001");
        dataFrmDb.Add("Country", new List<string> { "USA", "Bulgaria", "France" });
        dataFrmDb.Add("Document Type", "example");

        dictList.Add(dataFrmDb);
        return dictList;
    }
}

Output:

{
  "Documents": [
    {
      "Title": "An Example Document",
      "DatePublished": "4/9/2013 7:25:05 PM",
      "DocumentURL": "http://www.example.org/documents/1234",
      "ThumbnailURL": "http://www.example.org/thumbs/1234",
      "Abstract": "This is an example document.",
      "Sector": "001",
      "Country": [
        "USA",
        "Bulgaria",
        "France"
      ],
      "Document Type": "example"
    }
  ]
}

A somewhat more straightforward way to do it is to create separate classes to hold the data, as was suggested by Joey Gennari. Json.NET can serialize those as well. The data classes would look something like this:

class Result
{
    public List<Document> Documents { get; set; }

    public Result()
    {
        Documents = new List<Document>();
    }
}

class Document
{
    public string Title { get; set; }
    public string DatePublished { get; set; }
    public string DocumentURL { get; set; }
    public string ThumbnailURL { get; set; }
    public string Abstract { get; set; }
    public string Sector { get; set; }
    public List<string> Country { get; set; }
    [JsonProperty(PropertyName="Document Type")]
    public string DocumentType { get; set; }

    public Document()
    {
        Country = new List<string();
    }
}

And here is the usage:

class Program
{
    static void Main(string[] args)
    {
        Document doc = new Document();
        doc.Title = "An Example Document";
        doc.DatePublished = DateTime.Now.ToString();
        doc.DocumentURL = "http://www.example.org/documents/1234";
        doc.ThumbnailURL = "http://www.example.org/thumbs/1234";
        doc.Abstract = "This is an example document.";
        doc.Sector = "001";
        doc.Country.Add("USA");
        doc.Country.Add("Bulgaria");
        doc.Country.Add("France");
        doc.DocumentType = "example";

        Result result = new Result();
        result.Documents.Add(doc);

        string json = JsonConvert.SerializeObject(result, Formatting.Indented);
        System.Console.WriteLine(json);
    }
}

The output for this example is exactly the same as the first.

Joey Gennari · Accepted Answer · 2013-04-09 15:40:57Z

Here is a different way to solve it with DataContractJsonSerializer. First create a class to represent the object:

    [DataContract]
    public class DocumentHolder
    {
        [DataMember(Name = "Documents")]
        public Documents Document { get; set; }
    }

    [DataContract]
    public class Documents
    {
        [DataMember(Name = "Title", Order = 1)]
        public string Title { get; set; }
        [DataMember(Name = "DatePublished", Order = 2)]
        public DateTime? DatePublished { get; set; }
        [DataMember(Name = "DocumentURL", Order = 3)]
        public string DocumentURL { get; set; }
        [DataMember(Name = "ThumbnailURL", Order = 4)]
        public string ThumbnailURL { get; set; }
        [DataMember(Name = "Abstract", Order = 5)]
        public string Abstract { get; set; }
        [DataMember(Name = "Sector", Order = 6)]
        public string Sector { get; set; }
        [DataMember(Name = "Country", Order = 7)]
        public List<string> Country { get; set; }
        [DataMember(Name = "Document Type", Order = 8)]
        public string DocumentType { get; set; }

        public Documents()
        {
            this.Country = new List<string>();
        }
    }

Here's how you would fill the object and serialize it:

    static void Main(string[] args)
    {
        var documentholder = new DocumentHolder { Document = new Documents { Title = "Title 1", DatePublished = DateTime.Now, Sector = "A17", Country = new List<string> { "EN-US", "EN-GB" } } };
        DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(DocumentHolder));
        var ms = new MemoryStream();
        serializer.WriteObject(ms, documentholder);
        var text = Encoding.UTF8.GetString(ms.ToArray());
    }

I'm using .NET 3.5 I noticed that Data Contracts are for 4.0 and up is there another solution you have in mind?

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