public TService GetService<TService>()
where TService : class, IService

Public Function GetService(Of TService As {Class, IService}) As TService

public:
generic<typename TService>
where TService : ref class, IService
virtual TService GetService() sealed

abstract GetService : unit -> 'TService  when 'TService : not struct and IService
override GetService : unit -> 'TService  when 'TService : not struct and IService