Why LINQ to Entities won't let me initialize just some properties of an Entity?
- by emzero
So I've started to add Entity Framework 4 into a legacy web application (ASP.NET WebForms).
As a start I have auto-generated some entities from the database. Also I want to apply Repository Pattern.
There is an entity called Visitor and its repository VisitorRepository
In VisitorRepository I have the following method:
public IEnumerable<Visitor> GetActiveVisitors()
{
var visitors =
from v in _context.Visitors
where v.IsActive
select new Visitor
{
VisitorID = v.VisitorID,
EmailAddress = v.EmailAddress,
RegisterDate = v.RegisterDate,
Company = v.Company,
Position = v.Position,
FirstName = v.FirstName,
LastName = v.LastName
};
return visitors.ToList();
}
That List is then bound to a repeater and when trying to do <%# Eval('EmailAddress') #%> it throws the following exception.
The entity or complex type 'Model.Visitor' cannot be constructed in a LINQ to Entities query.
A) Why is this happening? How I can workaround this? Do I need to select an anonymous type and then use that to initialize my entities???
B) Why every example I've seen makes use of 'select new' (anonymous object) instead of initializing a known type? Anonymous types are useless unless you are retrieving the data and showing it in the same layer. As far as I know anonymous types cannot be returned from methods? So what's the real point of them???
Thank you all
