"Concretising" generics - for WPF service

(Looking for thoughts...)

So - when you create a WCF service with a [ServiceContract()] and [DataContract()] you can't use open generics - which I do understand why.

However - anyone have any ideas about how I could specify a small set of types and have the generics turned into concrete implementations in the service ? (Probably looking at codegen??)

i.e. if I have a function like Add(Of TParam)(Byval lhs As TParam, ByVal rhs As TParam) As TParam I'd like it to generate:-

AddInteger(Byval lhs As Integer, Byval rhs As Integer) As Integer

AddDouble(Byval lhs As Double, Byval rhs As Double) As Double

(etc.)

If it's a small number of types, just write them by hand. What does the implementation of that Add method look like? Is it really okay to send any type to it? I assume from the signature that it's arithmetic addition, rather than inclusion in a collection, at which point you have to ask what does it mean to add (for example) two FileSystemWatcher instances together?

I think the underlying problem is that you don't have a good candidate method for being generic.

"Add" was a (badly chosen) off the top of my head example.

The actual thing I want to "concretise" is the Query->QueryHandler link.

vb.net Code:

Public Function HandleQuery(Of TQuery As IQueryDefinition(Of TResult), TResult)(query As TQuery) As TResult

but yes - for the moment hand coding it will be as fast as writing some fancy code gen thing...

"vb.net Code:

<ServiceContract()>
Public Interface IQueryHandlerService
 
    ' Concrete query handler functions
    <WebGet(ResponseFormat:=WebMessageFormat.Json, UriTemplate:="Brokers?query={query}")>
    <OperationContract()>
    Function GetAllBrokersForClientQueryHandler(ByVal query As GetAllBrokersForClientQueryDefinition) As IEnumerable(Of DTO.Broker)
 
End Interface