Type parameter constraints: Controller where T: class, new (), type Parameter controller

Type parameter constraints: Controller where T: class, new (), type Parameter controller

Beginners do not understand: Controller where T: class, new (), and I do not understand it when I am a beginner. Here is a simple explanation:

This is a type parameter constraint ,. NET supports the following types of parameter constraints: where T: struct | T must be a structure type where T: class | T must be a class type, it cannot be a structure type where T: new () | T must have a no-argument constructor where T: NameOfBaseClass | T must inherit the class where T named NameOfBaseClass: nameOfInterface | T must implement the interface named NameOfInterface