Declaring Entity FrameWork Contexts with using

Question

Which is the Best Practise in Declaring Entity FrameWork Contexts

function()
{
    DBContext context = new DBContext();

    //Entity code

    return ;
}
         


        

Answer 1

Yes, a using is the best practice because it cleans up your context. The Using statement is a shortcut for:

try {
    // Execute your code inside the using statement
}
finally {
    // Cleanup the context no matter what by calling .Dispose()
}

Keep in mind, your context likely returns IEnumerables and since EF supports lazy loading these objects won't be populated until you fetch them to a concrete collection (ie. yourResult.ToList()).

A common negative outcome occurs in this scenario:

public IEnumerable GetEmployeesInAccounting()
{
    using(var myContext = new MyDbContext())
    {
        return myContext.Employees.Where(emp => emp.Department == 'Accounting');
    }
}

// Code that fails, Assuming Manager is a lazy loaded entity, this results in an exception but it compiles no problem
var acctEmps = GetEmployeesInAccounting();
var something = acctEmps.First().Department.Manager.Department;

You can avoid this by using the .Include(emp => emp.Manager) (linq extension method) and binding your result using .ToList();