using System;

using System.Linq;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""messages"": [

                {

                  ""type"": ""msgInfo"",

                  ""description"": ""Some stuff happened""

                },

                {

                  ""type"": ""msgInfo"",

                  ""description"": ""More stuff happened""

                },

                {

                  ""type"": ""msgInfo"",

                  ""description"": ""yup, more stuff happened""

                }

              ],

              ""results"": [

                {

                  ""parameterId"": ""val_1"",

                  ""dataType"": ""Double"",

                  ""value"": 123.45

                },

                {

                  ""parameterId"": ""val_2"",

                  ""dataType"": ""Double"",

                  ""value"": 246.8

                },

                {

                  ""parameterId"": ""val_3"",

                  ""dataType"": ""Double"",

                  ""value"": 135.79

                },

                {

                  ""parameterId"": ""val_4"",

                  ""dataType"": ""Long"",

                  ""value"": 20161021

                }

              ]

            }";

        JObject obj = JObject.Parse(json);

        JToken token = obj.SelectToken("$.results[?(@.parameterId=='val_1')].value");

        Console.WriteLine("using JSONPath: " + token.ToString());

        JToken token2 = obj["results"]

            .Where(result => (string)result["parameterId"] == "val_1")

            .Select(result => result["value"])

            .FirstOrDefault();

        Console.WriteLine("using LINQ:     " + token2.ToString());

    }

}