Read the Definition of dynamic Parameter-Fields via Code

I want to read the definition of the parameter fields. I use VB.NET/VS2010

The Name and some other helpfull informations i can meanwhile read and work with them. But I didn´t find the information where dynamic Paramters store the Query (example: Country => ZIPRange => City = Parameter 'CityName')

Where is defined the Query and how can I read it

Thank you very much