C# Generics - Constraints on type parameters

Question

I'm trying to build a factory method that uses the generics feature of C#.

In this factory method I would like to constraint it to some specific classes, all of which do not have a default constructor.

Here is my example. Can someone tell me if it's possible to run it?

public class AbstractClass {
    //this abstract class does not have a default constructor, nor its subclasses
    public AbstractClass(SomeClassName obj) {
        //use obj for initialization
    }
}

//this factory class should create objects of type T that inherit 
//from AbstractClass and invoke the non-default constructor
public class FactoryClass {
    public static T BuildObject<T> (SomeClassName obj) where T: AbstractClass {
        return new T(obj); //does not work?!?!?!
    }
}


//Edit: ANSWER!!!
public static T BuildObject<T>(SomeClassUsedForTheConstructor item) where T : SomeAbstractClass { 
return (T) Activator.CreateInstance(typeof (T), item); 
} 

Answer 1

I like to use Activator.CreateInstance(typeof(T)) in my generics that need to create new objects of type T. It works really well.