This question already has an answer here:
Hello from here I know that I can create an instance from a String:
How to get a Class name dynamically (from a string) in Dart, then create an instance?
but How do I create an instance of a Generic class from a String, ie:
var class_name = "GenericController<Book>"; // user input here
new class_name();
This is not currently possible (as you probably noticed). There's an open case in the Dart issue tracker you should Star to show your interest:
https://code.google.com/p/dart/issues/detail?id=12921