Why is the selector class an internal constructor?

Question

I tried to extract from the Selector class, I need the same functionality as the ListBox, but it is not a ListBox. I looked at the signature of the Selector class and this is (http://msdn.microsoft.com/en-us/library/system.windows.controls.primitives.selector(v=vs .95) .aspx)

public abstract class Selector : ItemsControl, 
ISupportInitialize

But the problem is that the constructor is internal. Thus, it is impossible to extract from this class outside the assembly (ListBox and ComboBox are in this assembly).

Now I got from ListBox to achieve my goal, but my question is:

Why is the selector class an internal constructor?

Answer 1

Selector abstract. , , ( ), - .

MSDN, , , , protected, internal.

, , Selector .

Edit: , internal, ...