using System;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Reflection;

public class Program

{

    public static void Main()

    {

        var p1 = new Person(){ Id = 1, FirstName = "Thanh", Roles = new List<string>(){ "Thanh1" }, Group = new Group(){ Name = "Group1" }, GroupDictionary = new Dictionary<string, Group>() { { "dic1", new Group() { Id = 1, Name = "group1" } }, { "dic2", new Group() { Id = 1, Name = "group2" } } }  };

        var p2 = new Person() { Id = 1, LastName = "Truong Duc", Roles = new List<string>() { "User" }, Group = new Group() { Id = 1 }, GroupDictionary = new Dictionary<string, Group>() { { "dic3", new Group() { Id = 3, Name = "group3" } } } } ;

        object p3;

        MergeObject(p1, p2, out p3, typeof(Person));

        Console.WriteLine(JsonConvert.SerializeObject(p3));

        Console.WriteLine(((Person)p3).FirstName);

    }

    private static void MergeObject(object obj1, object obj2, out object obj, Type type)

        {

            Console.WriteLine(JsonConvert.SerializeObject(obj1));

            Console.WriteLine(JsonConvert.SerializeObject(obj2));

            var properties = type.GetProperties().Where(x=>x.CanWrite).ToList();

            Console.WriteLine(JsonConvert.SerializeObject(properties.Select(x=>x.PropertyType.FullName).ToList()));

            var objDefault = Activator.CreateInstance(type);

            obj = Activator.CreateInstance(type);

            foreach (var prop in properties)

            {

                var propValueDefault = prop.GetValue(objDefault);

                var propValue = prop.GetValue(obj1);

                Console.WriteLine(typeof(IEnumerable).IsAssignableFrom(prop.PropertyType));

                if(propValue == null){

                    propValue = prop.GetValue(obj2);

                } else if(isDictionary(prop)){

                    Console.WriteLine("DICTIONARY " + prop.PropertyType);

                    var propObj2Value = prop.GetValue(obj2) as IDictionary;

                    ((IDictionary)propValue).MergeDictionary(propObj2Value);

                }

                else if(isCollection(prop)) // check prop is a collection

                {

                    Console.WriteLine("class" + prop.PropertyType);

                    var propObj2Value = prop.GetValue(obj2) as IList;

                    ((IList)propValue).MergeList(propObj2Value);

                }else if(isChildClass(prop)){

                    Console.WriteLine("class" + prop.PropertyType);

                    var propObj2Value = prop.GetValue(obj2);

                    if(propObj2Value != null){

                        MergeObject(propValue, propObj2Value, out propValue, prop.PropertyType);

                    }

                }

                else

                {

                    if(propValue.Equals(propValueDefault))

                    {

                        Console.WriteLine("default: " + propValueDefault);

                        propValue = prop.GetValue(obj2);

                    }

                }

                prop.SetValue(obj, propValue);

            }

        }

        private static bool isCollection(PropertyInfo propertyInfo)

        {

            return propertyInfo.PropertyType != typeof(string) && typeof(IEnumerable).IsAssignableFrom(propertyInfo.PropertyType);

        }

        private static bool isDictionary(PropertyInfo propertyInfo)

        {

            return propertyInfo.PropertyType.IsGenericType && typeof(IDictionary).IsAssignableFrom(propertyInfo.PropertyType);

        }

        private static bool isChildClass(PropertyInfo propertyInfo)

        {

            return (propertyInfo.PropertyType.IsClass && !propertyInfo.PropertyType.IsValueType &&

                                !propertyInfo.PropertyType.IsPrimitive && propertyInfo.PropertyType.FullName != "System.String");

        }

}

​

public class Person 

{

    public int Id { get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string Address1 { get; set; }

    public string Address2 { get; set; }

    public List<string> Roles {get;set;}

    public Group Group{get;set;}

    public Dictionary<string, Group> GroupDictionary {get; set; }

    public Person(){}

}

​

public class Group{

    public int Id {get;set;}

    public string Name{ get;set;}

    public Group(){}

}

​

public static class MergeExtensions

{

     public static IDictionary MergeDictionary(this IDictionary propValue, IDictionary propObj2Value)

     {

         if (propObj2Value != null)

         {

             if (propValue == null)

             {

                 propValue = propObj2Value;

             }

             else

             {

                 foreach (var key in propObj2Value.Keys)

                 {

                     if (!(propValue).Contains(key))

                     {

                         (propValue).Add(key, propObj2Value[key]);

                     }

                 }

             }

         }

​

         return propValue;

     }

    public static IList MergeList(this IList propValue, IList propObj2Value)

    {

        if (propObj2Value != null)

        {

            if (propValue == null){

                propValue = propObj2Value;

            }else{

                Console.WriteLine(JsonConvert.SerializeObject(propObj2Value));

                Console.WriteLine(JsonConvert.SerializeObject(propValue));

                foreach (var item in propObj2Value)

                {

                    (propValue as IList).Add(item);

                }

​

            }

            Console.WriteLine(JsonConvert.SerializeObject(propValue));

        }else{

            Console.WriteLine("propObj2Value is NULL");

        }

        return propValue;

    }

}