json.md

Working with JSON in C#

Encoding and Decoding JSON with Native Libraries

There are lots of third party JSON libraries out there, but I prefer to use the ones that come with Visual Studio.

using System.Web.Script.Serialization;

Constructing JSON from Scratch

JavaScriptSerializer serializer = new JavaScriptSerializer();
string serializedResult = serializer.Serialize(RegisteredUsers);
//serializedResult = JsonPrettify(serializedResult);
Console.WriteLine(serializedResult);

Decoding JSON

List<Person> deserializedObjects = serializer.Deserialize<List<Person>>(serializedResult);
foreach (Person person in deserializedObjects)
    Console.WriteLine(person.Name);

Person class

For reference, here's the code that made-up the RegisteredUsers List and the Person class:

class Person
{
    public int PersonID;
    public string Name;
    public bool Registered;
}

List<Person> RegisteredUsers = new List<Person>();
RegisteredUsers.Add(new Person() { PersonID = 1, Name = "Bryon Hetrick", Registered = true });
RegisteredUsers.Add(new Person() { PersonID = 2, Name = "Nicole Wilcox", Registered = true });
RegisteredUsers.Add(new Person() { PersonID = 3, Name = "Adrian Martinson", Registered = false });

Prettify Json

public static string prettifyJson(string json, int indentCount = 4, char indentChar = ' ')
{
    json = json.Replace("\\,", "~EscapedComma~");
    json = json.Replace(":{", "~ColonStartBracket~\n");
    json = json.Replace("},", "~EndBracketComma~");
    json = json.Replace(":[", "~ColonStartSquareBracket~\n");
    json = json.Replace("],", "~EndSquareBracketComma~");
    json = json.Replace(",", ",\n");
    json = json.Replace("{", "\n{\n");
    json = json.Replace("}", "\n}\n");
    json = json.Replace("[", "\n[\n");
    json = json.Replace("]", "\n]\n");
    json = json.Replace("~ColonStartBracket~", ": {");
    json = json.Replace("~EndBracketComma~", "\n},\n");
    json = json.Replace("~ColonStartSquareBracket~", ": [");
    json = json.Replace("~EndSquareBracketComma~", "\n],\n");
    json = json.Trim();
    string[] lines = json.Split('\n');

    int bracketsDeep = 0;
    for (int i = 0; i < lines.Length; i++)
    {
        string line = lines[i].Trim();
        int indentLevel = bracketsDeep;
        if (line.StartsWith("{") || line.EndsWith("{") || line.StartsWith("[") || line.EndsWith("["))
        {
            bracketsDeep += 1;
            indentLevel = bracketsDeep - 1;
        }
        else if (line.EndsWith("}") || line.EndsWith("},") || line.EndsWith("]") || line.EndsWith("],"))
        {
            bracketsDeep -= 1;
            indentLevel = bracketsDeep;
        }
        string padding = String.Concat(Enumerable.Repeat(indentChar, indentLevel * indentCount));
        lines[i] = padding + line;
    }
    json = String.Join("\r\n", lines);

    return json;
}

Example Input

{"messageType":"response","request":{"messageType":"request","action":"scanFolderFast","path":"D:\\demoData\\abfs-real","identifier":"17703011.abf","value":"1234","elapsedMsec":7.9362},"AbfFolder":{"path":"D:\\demoData\\abfs-real","fileNames":null,"folderNames":null},"elapsedMsec":4.5174}

Example Output

{
    "messageType":"response",
    "request": {
        "messageType":"request",
        "action":"scanFolderFast",
        "path":"D:\\demoData\\abfs-real",
        "identifier":"17703011.abf",
        "value":"1234",
        "elapsedMsec":7.2797
    },
    "AbfFolder": {
        "path":"D:\\demoData\\abfs-real",
        "fileNames":null,
        "folderNames":null
    },
    "elapsedMsec":4.0363
}

Nesting JSON

The serializer is a simple way to turn a class into a JSON string. To create nested JSON, put classes inside other classes and serialize the whole thing.

First create nested classes...

public class Names
{
    public string name1 = "alpha";
    public string name2 = "bravo";
    public string name3 = "charley";
    public string name4 = "delta";
}

public class Request
{
    public readonly Action action;
    public readonly string path;
    public readonly string identifier;
    public readonly string value;
    public readonly Names names;
    public readonly int coolNumber;

    public Request(Action action, string path = null, string identifier = null, string value = null)
    {
        this.action = action;
        this.path = path;
        this.identifier = identifier;
        this.value = value;
        names = new Names();
        coolNumber = 12345;
    }
}

Then serialize the top class...

JavaScriptSerializer serializer = new JavaScriptSerializer();
string json = serializer.Serialize(this); // a class can serialize itself!!!
Console.WriteLine(json);

Output

{
  "action":0,
  "path":"Path",
  "identifier":"17703011.abf",
  "value":"1234",
  "names":{
    "name1":"alpha",
    "name2":"bravo",
    "name3":"charley",
    "name4":"delta"
  },
  "coolNumber":12345
}