Entity Framework: How to include nested child during add or update data to db

Question

this below way i am inserting customer and nested child. customer has child called address and address has child called contacts details.

    using (var db = new TestDBContext())
    {
        var customer = new Customer
        {
            FirstName = "Test Customer1",
            LastName = "Test Customer1",
            Addresses = new List<Addresses>
            {
                new Addresses
                {
                    Address1 = "test add1",
                    Address2 = "test add2",
                    IsDefault=true,
                    Contacts =  new List<Contacts>
                    {
                       new Contacts {  Phone = "1111111", Fax = "1-1111111",IsDefault=true, SerialNo=1 },
                       new Contacts {  Phone = "2222222", Fax = "1-2222222",IsDefault=false, SerialNo=2  }
                    }
                },
                new Addresses
                {
                    Address1 = "test add3",
                    Address2 = "test add3",
                    IsDefault=false,
                    Contacts =  new List<Contacts>
                    {
                       new Contacts {  Phone = "33333333", Fax = "1-33333333",IsDefault=false, SerialNo=1 },
                       new Contacts {  Phone = "33333333", Fax = "1-33333333",IsDefault=true, SerialNo=2  }
                    }
                }

            }
        };

        db.Customer.Add(customer);
        db.SaveChanges();

        int id = customer.CustomerID;
    }

suppose now i want to update customer and its associated address and contacts details.

i browser few similar thread here. i saw people deleting child data and insert new one instead of update. here is one link https://stackoverflow.com/a/27177623/728750

they include child this way

var existingParent = _dbContext.Parents
        .Where(p => p.Id == model.Id)
        .Include(p => p.Children)
        .SingleOrDefault();

but in my case i have multiple child say like address and contact details then how could i Include first address of customer and then i like to include contact details child of address.

please tell me how to do it.

Answer 1

Are you looking for this

using System.Data.Entity; // NB!

var company = dbContext.Parents
                     .Include(co => co.Addresses.Select(ad=> ad.Contacts))
                     .FirstOrDefault(p =>  p.Id == model.Id);

Brief sample

var company = context.Companies
                 .Include(co => co.Employees.Select(emp => emp.Employee_Car))
                 .Include(co => co.Employees.Select(emp => emp.Employee_Country))
                 .FirstOrDefault(co => co.companyID == companyID);

.Include Msdn details summarized

To include a collection, a collection, and a reference two levels down: query.Include(e => e.Level1Collection.Select(l1 => l1.Level2Collection.Select(l2 => l2.Level3Reference)))