[Solved]-Create a list nested within an object in a LINQ query-LINQ,C#

You can create House objects in your select statement. The code below creates a list of House objects each containing the appropriate names:

class Program
{
    static void Main(string[] args)
    {
        List<KeyValuePair<int, int>> housePersonPairs = new List<KeyValuePair<int, int>>();
        housePersonPairs.Add(new KeyValuePair<int, int>(1, 11));
        housePersonPairs.Add(new KeyValuePair<int, int>(1, 12));
        housePersonPairs.Add(new KeyValuePair<int, int>(1, 13));
        housePersonPairs.Add(new KeyValuePair<int, int>(2, 232));
        housePersonPairs.Add(new KeyValuePair<int, int>(2, 5533));
        housePersonPairs.Add(new KeyValuePair<int, int>(2, 40));

        List<Person> persons = new List<Person>();
        persons.Add(new Person() { ID = 11, Name = "John" });
        persons.Add(new Person() { ID = 12, Name = "Jane" });
        persons.Add(new Person() { ID = 13, Name = "Zoe" });
        persons.Add(new Person() { ID = 232, Name = "Name1" });
        persons.Add(new Person() { ID = 5533, Name = "Name2" });
        persons.Add(new Person() { ID = 40, Name = "Name3" });

        var houseAndNames = housePersonPairs.Join(
            persons,
            hpp => hpp.Value,
            p => p.ID, 
            (hpp, p) => new { HouseID = hpp.Key, Name = p.Name });

        var groupedNames = from hn in houseAndNames
                     group hn by hn.HouseID into groupOfNames
                     select groupOfNames.Select(x => x.Name).ToList();

        List<House> houses = groupedNames.Select(names => new House() { people_name = names }).ToList();

    }
}

public class Person
{
    public int ID { get; set; }
    public string Name { get; set; }
}

public class House
{
    public List<string> people_name { get; set; }
}