Merge JSON string list result from into a single JSON with one root

Question

I have list JSON string, I want to merge them into a single JSON array.

I am getting a result from an API and need to iterate the result string to get one single result string

I have a list string and I need to iterate it and convert the list string into a single string with one root element and result merged with in it

using Newtonsoft.Json;
using System;
using System.Collections.Generic;

namespace ConsoleApp5
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Hello World!");
            MergeJsonResult();
        }
        private static void MergeJsonResult()
        {
            List<string> jsonResult = new List<string>();
            jsonResult.Add("{\n  \"arrayResult\": [\n    {\"Item1\": \"123\",\n    \"Item2\": \"858\",\n    \"Item3\": \"789\"\n    },\n    {\"Item1\": \"2588\",\n    \"Item2\": \"858\",\n    \"Item3\": \"587\"\n    }\n  ]\n}");
            jsonResult.Add("{\n  \"arrayResult\": [\n    {\"Item1\": \"123\",\n    \"Item2\": \"858\",\n    \"Item3\": \"789\"\n    },\n    {\"Item1\": \"2588\",\n    \"Item2\": \"858\",\n    \"Item3\": \"587\"\n    }\n  ]\n}");
            jsonResult.Add("{\n  \"arrayResult\": [\n    {\"Item1\": \"123\",\n    \"Item2\": \"858\",\n    \"Item3\": \"789\"\n    },\n    {\"Item1\": \"2588\",\n    \"Item2\": \"858\",\n    \"Item3\": \"587\"\n    }\n  ]\n}");

            foreach (var eachJson in jsonResult)
            {
                //Wat to merge JSON string
            }
            //Result should be with one root "arrayResult" and with in that the result array merged
        }
    }
}

**Result**
*Input*

 - String1

{
  "arrayResult": [
    {
      "Item1": "123",
      "Item2": "858",
      "Item3": "789"
    },
    {
      "Item1": "2588",
      "Item2": "858",
      "Item3": "587"
    }
  ]
}
- String2

{
  "arrayResult": [
    {
      "Item1": "123",
      "Item2": "858",
      "Item3": "789"
    },
    {
      "Item1": "2588",
      "Item2": "858",
      "Item3": "587"
    }
  ]
}
- String3

{
  "arrayResult": [
    {
      "Item1": "123",
      "Item2": "858",
      "Item3": "789"
    },
    {
      "Item1": "2588",
      "Item2": "858",
      "Item3": "587"
    }
  ]
}

*Output*
- Merged string with one root 

{
  "arrayResult": [
    {
      "Item1": "123",
      "Item2": "858",
      "Item3": "789"
    },
    {
      "Item1": "2588",
      "Item2": "858",
      "Item3": "587"
    },
    {
      "Item1": "123",
      "Item2": "858",
      "Item3": "789"
    },
    {
      "Item1": "2588",
      "Item2": "858",
      "Item3": "587"
    },
    {
      "Item1": "123",
      "Item2": "858",
      "Item3": "789"
    },
    {
      "Item1": "2588",
      "Item2": "858",
      "Item3": "587"
    }
  ]
}

Answer 1

Solution 1: LINQ approach

1. In jsonResult list, parse each item (JSON string) to JObject.

2. From result 1, extract the value of arrayResult as JToken. It returns the items in arrayResult array as List<JToken>.

3. Create an object with arrayResult property which holds the result from 2.

using System.Collections.Generic;
using System.Linq;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

List<JToken> items = jsonResult.Select(x => JObject.Parse(x))
    .SelectMany(x => x["arrayResult"])
    .ToList();
        
dynamic result = new {
    arrayResult = items 
};

Demo Solution 1 @ .NET Fiddle

---

Solution 2: foreach loop approach

1. Create an object with arrayResult property which holds the array.

2. Iterate each element in jsonResult, parse JSON string to JObject, extract the arrayResult value from JObject. This returns list of items. Then you need to .AddRange() to add the items list to result.arrayResult.

dynamic result = new {
    arrayResult = new List<dynamic>()   
};
        
foreach (var eachJson in jsonResult)
{
    result.arrayResult.AddRange(JObject.Parse(eachJson)
                                .SelectToken("arrayResult")
                                .ToList());
}

Demo Solution 2 @ .NET Fiddle