Entity MVC and ViewModels one to many example - asp.net

Question

I have a simple example
I want to display a list of companies and employees
ACME
David
Simon
Zac
Microsoft
Kevin
Paul
Currently I do a linq query that returns the company model then traverse the model tree to get the employees. This works fine, however using glimpse I see its doing in the above example 3 queries. One for company then 2 queries for employees one for each company.
Im wondering if I would be better off having a ViewModel representing the data and populating that. However when trying to build the view model I dont know how to build it without doing multiple queries.
var data =
from company in db.Companies
join employee in db.Employees on company.companyId equals employee.companyId
orderby company.name, employee.name
select new { companyName = company.name, employeeName = employee.name }
Is there an easy way to link this to the view model or is there another best practice way of doing something simple like this.

Answer 1

You can get data in one round trip from database by adding ToList():
var data =
(from company in db.Companies
join employee in db.Employees on company.companyId equals employee.companyId
orderby company.name, employee.name
select new { companyName = company.name, employeeName = employee.name }).ToList();
or get company type instead of anonymous type
var data = db.Companies.Include(t => t.Employees )
.Select(t => new
{
t.name,
Employees = t.Employees .Select(p => new { p.name})
}).ToList();
or if you wanna use ViewModel, create a viewmodel:
public class CompanyVm
{
public string name { get; set; }
public IEnumerable<Employee> Employees{ get; set; }
}
public class Employee
{
public string name { get; set; }
}
then use automapper to map data
var comVm = data
.Select(comp => AutoMapper.Mapper.DynamicMap(comp, comp.GetType(), typeof(CompanyVm)))
.Select(comp => comp as CompanyVm).ToList();

Answer 2

Assuming you have the navigation properties in Entity Framework wired up correctly, you should be able to do:
var data = db.Companies
.Include(i => i.Employees)
.Tolist();
Then you can loop through them:
foreach (var company in data)
{
foreach (var employee in company.Employees)
{
}
}
Don't forget to include using System.Data.Entity; or you won't be able to use the strong-typed .Include() method.