Q & A on last post (Duck Typing)

My last post on duck typing generated this question:

I have a question regarding your recent post about Duck Typing and anonymous type scope in C# 4.0.  Does this now open up the possibility of using an anonymous type (say, the results of a LINQ query) outside the scope of the method it was created?  Something like the following using the example in your post:

 1: public static void PrintLabel(dynamic thing)

 2: {

 3: Console.WriteLine("ID: {0}, Label: {1}", thing.ID, thing.Label);

 4: }

 5:  

 6: public void GetAnAnonymousType(string key)

 7: {

 8: var item = (from application in _Repository.GetApplications()

 9: where application.ApplicationKey == key

 10: select new

 11: {

 12: ID = application.ApplicationId,

 13: Label = application.LastName

 14: }).SingleOrDefault();

 15:  

 16: PrintLabel(item);

 17: }

Very simply, yes. This construct is a great use of dynamic types in C#. Dynamic provides a form of escape hatch into a a world where your types can be tested at runtime.