Generic Constraints

Constraint	Meaning in Life
where T : struct	The type parameter <T> must have System.ValueType in its chain of inheritance.
where T : class	The type parameter <T> must not have System.ValueType in its chain of inheritance (e.g., <T> must be a reference type).
where T : new()	The type parameter <T> must have a default constructor. This is very helpful if your generic type must create an instance of the type parameter, as you cannot assume the format of custom constructors. Note that this constraint must be listed last on a multiconstrained type.
where T : NameOfBaseClass	The type parameter <T> must be derived from the class specified by NameOfBaseClass.
where T : NameOfInterface	The type parameter <T> must implement the interface specified by NameOfInterface.

The syntax for defining both inheritance and constraints is:

   class FSM : AbstractFSM, INotifyPropertyChanged
      where TState : struct
      where TEvent : struct
   {

To define multiple constraints for a single type parameter separate them with commas. It seems like "new()" has to be the last in the list.

      private void CollectionConstructorTest()
         where TVCollection : VCollection, new()
         where TVClass : VClass, new()
      {