Is there any way to dynamically create properties from Json string in Winforms using C#?

Question

There is a method in our application that returns api object schema as json. I am trying to figure out if there is anyway to pull out the property names. For instance, I receive the following json text (after deserialization):

 "json": {
        "CompanyId": null,
        "Name": null,
        "UniqueIdentity": null,
        "AccountCode": null,
        "IsActive": null,
        "ContractNumber": null,
        "IsSiteCompany": null,
        "TaxCode": null,
        "GLCode": null,
        "CompanyTypeId": null,
        "AddressInfo": [
            {
                "AddressId": null,
                "CompanyId": null,
                "AddressTypeId": null,
                "Phone": null,
                "Fax": null,
                "Address": null,
                "Address2": null,
                "City": null,
                "State": null,
                "Zip": null,
                "Country": null
            }
        ],
        "ContactInfo": [
            {
                "ContactId": null,
                "CompanyId": null,
                "ContactTypeId": null,
                "FirstName": null,
                "MiddleName": null,
                "LastName": null,
                "Alias": null,
                "Position": null,
                "Email": null,
                "Phone": null,
                "IsPrimaryContact": null
            }
        ]

I need to pull out the property names like CompanyId, Name, etc. I know I can create a class and deserialize into the class object, the problem is, I never know what the schema will be. It will not always be what is above. I know I can pick the text apart bit by bit to come up with the property names, but I was wondering if anyone knew of anything that already exists that can accomplish this task.

If you never know what the schema will be, how will you know which properties to drill into? — Jonathon Chase, Mar 25 '19 at 19:23
Have a look at this https://stackoverflow.com/questions/21002297/getting-the-name-key-of-a-jtoken-with-json-net — gsharp, Mar 25 '19 at 19:26
@JonathonChase - that is exactly the question. I'm trying to find out if there is a way to retrieve the property names. — Rani Radcliff, Mar 25 '19 at 19:27
@JonathonChase incorrect. There are a ton of JSON tools that can at runtime dynamically drill into JSON hierarchies without knowing the schema at compile-time — , Mar 25 '19 at 20:09
@MickyD I didn't mean to suggest there were no tools, I was looking to clarify what the plan to approach dynamically parsing was. — Jonathon Chase, Mar 25 '19 at 20:21

score 1 · Answer 1 · answered Mar 25 '19 at 19:34

You are looking at JObject.Properties(). Parse your JSON as a JObject, then walk through it.

Sample code:

using System;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

namespace JsonParse
{
    class Program
    {
        static void Main(string[] args)
        {
            string json = @"{
                CPU: 'Intel',
                Drives: [
                    'DVD read/writer',
                    '500 gigabyte hard drive'
                ]
                }";
            JObject o = JObject.Parse(json);
            foreach (var prop in o.Properties())
            {
                Console.WriteLine(prop.Name);
            }
        }
    }
}

Thank you. This works great for the "Top" properties, but it does not get the names of child objects, but it is a great start. Thanks again! — Rani Radcliff, Mar 25 '19 at 19:55

score 1 · Accepted Answer · answered Mar 25 '19 at 20:59

You can implement Visitor pattern (something similar to ExpressionVisitor):

public class JsonVisitor
{
    private readonly HashSet<string> uniqueProperties;
    private readonly List<string> allProperties;

    public JsonVisitor()
    {
        uniqueProperties = new HashSet<string>();
        allProperties = new List<string>();
    }

    public string UniqueProperties => string.Join(Environment.NewLine, uniqueProperties);
    public string AllProperties => string.Join(Environment.NewLine, allProperties);

    public void Visit(JObject jObject)
    {
        uniqueProperties.Clear();
        allProperties.Clear();

        VisitObject(jObject, "");
    }

    private void VisitObject(JObject jObject, string currentPath)
    {
        foreach (var property in jObject.Properties())
        {
            uniqueProperties.Add(property.Name);
            var path = $"{currentPath}/{property.Name}";
            allProperties.Add(path);

            VisitToken(property.Value, path);
        }
    }

    private void VisitArray(JArray jArray, string currentPath)
    {
        for (var i = 0; i < jArray.Count; ++i)
        {
            var item = jArray[i];
            var path = $"{currentPath}[{i}]";
            VisitToken(item, path);
        }
    }

    private void VisitToken(JToken token, string currentPath)
    {
        if (token is JObject childObject)
            VisitObject(childObject, currentPath);
        else if (token is JArray childArray)
            VisitArray(childArray, currentPath);

    }
}

Usage:

var input = "{\r\n  \"json\":{\r\n    \"CompanyId\":null,\r\n    \"Name\":null,\r\n    \"UniqueIdentity\":null,\r\n    \"AccountCode\":null,\r\n    \"IsActive\":null,\r\n    \"ContractNumber\":null,\r\n    \"IsSiteCompany\":null,\r\n    \"TaxCode\":null,\r\n    \"GLCode\":null,\r\n    \"CompanyTypeId\":null,\r\n    \"AddressInfo\":[\r\n      {\r\n        \"AddressId\":null,\r\n        \"CompanyId\":null,\r\n        \"AddressTypeId\":null,\r\n        \"Phone\":null,\r\n        \"Fax\":null,\r\n        \"Address\":null,\r\n        \"Address2\":null,\r\n        \"City\":null,\r\n        \"State\":null,\r\n        \"Zip\":null,\r\n        \"Country\":null\r\n      }\r\n    ],\r\n    \"ContactInfo\":[\r\n      {\r\n        \"ContactId\":null,\r\n        \"CompanyId\":null,\r\n        \"ContactTypeId\":null,\r\n        \"FirstName\":null,\r\n        \"MiddleName\":null,\r\n        \"LastName\":null,\r\n        \"Alias\":null,\r\n        \"Position\":null,\r\n        \"Email\":null,\r\n        \"Phone\":null,\r\n        \"IsPrimaryContact\":null\r\n      }\r\n    ]\r\n  }\r\n}";
var json = JObject.Parse(input);

var visitor = new JsonVisitor();
visitor.Visit(json);

Console.WriteLine($"Unique properties:\r\n{visitor.UniqueProperties}");
Console.WriteLine();
Console.WriteLine($"All properties:\r\n{visitor.AllProperties}");

Output:

Unique properties:
json
CompanyId
Name
UniqueIdentity
AccountCode
// and so on

All properties:
/json
/json/CompanyId
/json/Name
/json/UniqueIdentity
/json/AccountCode
/json/IsActive
/json/ContractNumber
/json/IsSiteCompany
/json/TaxCode
/json/GLCode
/json/CompanyTypeId
/json/AddressInfo
/json/AddressInfo[0]/AddressId
/json/AddressInfo[0]/CompanyId
/json/AddressInfo[0]/AddressTypeId
/json/AddressInfo[0]/Phone
/json/AddressInfo[0]/Fax
// and so on

Is there any way to dynamically create properties from Json string in Winforms using C#?

2 Answers2