Question

I have some class, for example A, and others who extended A (A1,A2). The A is a container – it has only fields, any methods and properties.

Another class is B<T> where T : A, and extends of B (B1, B2)

Is it possible do that in c#?

public List<T<T1>> DoSomething(object parameter) 
                                      where T : B<T1>, new() where T1 : A, new()

In that method i must dynamic create T (B1 or B2 or B3) object and fill that generic object dynamic created T1 objects (A1, A2, A3). Yup i probably can use Activator, but use new T() will be better and use less casts

Answer 1

You don’t need T<T1>

To clean it up a little:

public List<T> DoSomething<T, T1>(object parameter) 
      where T : B<T1>, new()   // this specifies T<T1> already
      where T1 : A, new()
{
}

And assuming A and B have default constructors, you don’t need the new() constraints.