Is it possible to use generic support with single table inheritance, and still be able to FindAll of the base class?
As a bonus question, will I be able to use ActiveRecord开发者_如何转开发LinqBase<> as well? I do love those queries.
More detail: Say I have the following classes defined:
public interface ICompany
{
int ID { get; set; }
string Name { get; set; }
}
[ActiveRecord("companies",
DiscriminatorColumn="type",
DiscriminatorType="String",
DiscriminatorValue="NA")]
public abstract class Company<T> : ActiveRecordBase<T>, ICompany
{
[PrimaryKey]
private int Id { get; set; }
[Property]
public String Name { get; set; }
}
[ActiveRecord(DiscriminatorValue="firm")]
public class Firm : Company<Firm>
{
[Property]
public string Description { get; set; }
}
[ActiveRecord(DiscriminatorValue="client")]
public class Client : Company<Client>
{
[Property]
public int ChargeRate { get; set; }
}
This works fine for most cases. I can do things like:
var x = Client.FindAll();
But sometimes I want all of the companies. If I was not using generics I could do:
var x = (Company[]) FindAll(Company);
Client a = (Client)x[0];
Firm b = (Firm)x[1];
Is there a way to write a FindAll that returns an array of ICompany's that can then be typecast into their respective types?
Something like:var x = (ICompany[]) FindAll(Company<ICompany>);
Client a = (Client)x[0];
Or maybe I am going about implementing the generic support all wrong?
How about this:
[ActiveRecord("companies",
DiscriminatorColumn="type",
DiscriminatorType="String",
DiscriminatorValue="NA")]
public abstract class Company : ActiveRecordBase<Company>, ICompany {
[PrimaryKey]
private virtual int Id { get; set; }
[Property]
public virtual String Name { get; set; }
}
[ActiveRecord(DiscriminatorValue="firm")]
public class Firm : Company {
[Property]
public virtual string Description { get; set; }
}
[ActiveRecord(DiscriminatorValue="client")]
public class Client : Company {
[Property]
public virtual int ChargeRate { get; set; }
}
var allClients = ActiveRecordMediator<Client>.FindAll();
var allCompanies = ActiveRecordMediator<Company>.FindAll(); // Gets all Companies (Firms and Clients). Same as Company.FindAll();
Note that you can't just downcast your Companies as Clients or Firms, you need to use proper polymorphism or a visitor. See this for an explanation.
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