How to make categories, subcategories, subsubcategories with mvc?

I have three classes

public class CountryListViewModel
{
    public IEnumerable<CountryViewModel>
    Countries { get; set; }
}

public class CountryViewModel
{
    public string CountryName { get; set; }
    public string State { get; set; }
    public IEnumerable<CityViewModel> Cities { get; set; }
}

public class CityViewModel
{
    public string CityName { get; set; }
    public string CityLink { get; set; }
}

Using linq to entity grouping by country and it works as designed. but I also have to group by state. Could you please help me to change my query to group first by country and than by state?

var query = from c in _db.MyTable
                        where c.IsActive && c.Country == country 
                        group c by c.Country
                            into loc
                   开发者_运维知识库         select new CountryViewModel()
                            {
                                CountryName = loc.Key,
                                Cities = loc.Select(s => new CityViewModel() { CityName = s.City, CityLink = s.City }).Distinct()
                            };

I found solution by myself

var query = from c in _db.MyTable
            where c.IsActive && c.Country == country 
            group c by new{ c.Country, c.State}
            into loc
                    select new CountryViewModel()
                                {
                                    CountryName = loc.Key.Country,
    State = loc.Key.State,
                                    Cities = loc.Select(s => new CityViewModel() { CityName = s.City, CityLink = s.City }).Distinct()
                                };

var q = from i in query 
        group i by i.state into st 
        select new with { .State = st.Key,
                          .Countries = (from c in st group c by c.Country into ctr 
                                        select new with {.Country = ctr.Key,
                                        .Cities = ctr})

No Idea if this works, just typed it in here without testing or looking at your datamodel.