using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var currentList = new List<VendorAccess>(){new VendorAccess(1),new VendorAccess(2),new VendorAccess(3),new VendorAccess(4),new VendorAccess(5)};

        var entities = new List<VendorAccess>(){new VendorAccess(3),new VendorAccess(4),new VendorAccess(5),new VendorAccess(6),new VendorAccess(7),new VendorAccess(8),new VendorAccess(9)};

        var toRemove = new List<VendorAccess>(currentList);

        toRemove.RemoveAll(item => entities.Select(x=>x.VendorId).Contains(item.VendorId));

        var toAdd = new List<VendorAccess>(entities);

        toAdd.RemoveAll(item => currentList.Select(x=>x.VendorId).Contains(item.VendorId));

        Console.WriteLine("=============================");

        Console.WriteLine("REMOVE");

        Console.WriteLine("=============================");

        foreach(var i in toRemove){

         Console.WriteLine(i.VendorId);

        }

        Console.WriteLine("=============================");

        Console.WriteLine("Add");

        Console.WriteLine("=============================");

        foreach(var i in toAdd){

         Console.WriteLine(i.VendorId);

        }

    }

    public class VendorAccess{

        public VendorAccess(int i){

            VendorId = i;

        }

        public int VendorId {get;set;}  

    }

}