using System;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""config"": {

                ""DataSource"": {

                  ""connectionString"": ""Localserver"",

                  ""sqlExpression"": ""select id As 'key', logHeader As 'Label' from Log""

                }

              }

            }";

​

        JObject result = JObject.Parse(json);

        string connectionString = (string)result.SelectToken("config.DataSource.connectionString");

        string sqlExpression = (string)result.SelectToken("config.DataSource.sqlExpression");

        Console.WriteLine("Connection String : " + connectionString);

        Console.WriteLine("   SQL Expression : " + sqlExpression);

    }

}