Returning Anonymous Type
I am using a trick to return Anonymous Type but, i m not sure whether it will work in all scenario. If there is any problem using this trick plz let me know so that i will not use this code in my project
class A
{
public int ID { get; set; }
public string Name { get; set; }
}
class B
{
public int AID { get; set; }
public string Address { get; set; }
}
private List<object> GetJoin()
{
var query = from a in objA
join b in objB
on a.ID equals b.AID
select new { a.ID, a.Name, b.Address };
List<object> lst = new List<object>();
foreach (var item in query)
{
object obj = new { ID = item.ID, Name = item.Name, Address = item.Address };
开发者_如何学C lst.Add(obj);
}
return lst;
}
T Cast<T>(object obj, T type)
{
return (T)obj;
}
//call Anonymous Type function
foreach (var o in GetJoin())
{
var typed = Cast(o, new { ID = 0, Name = "", Address = "" });
int i = 0;
}
Yes, that's guaranteed to work so long as everything is within the same assembly. If you cross the assembly boundary, it won't work though - anonymous types are internal, and the "identity" is based on:
- Assembly it's being used in
- Properties:
- Name
- Type
- Order
Everything has to be just right for the types to be considered the same.
It's not nice though. For one thing, your GetJoin method can be simplified to:
return (from a in objA
join b in objB
on a.ID equals b.AID
select (object) new { a.ID, a.Name, b.Address })
.ToList();
... and for another, you've lost compile-time type safety and readability.
I think you'd be a lot better off creating a real type to encapsulate this data. Admittedly it would be lovely if we could create a named type which was the equivalent to the anonymous type, just with a name... but that's not available at the moment :(
You cannot return Anonymous Types without using Object type. And using Object type, you lose member access.
You have two options:
- Create a type. (Recommended)
- Use dynamic type to access members
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