Send extra parameter(s) in BCS/BDC-call to WCF-service

Question

Ok, this question got lengthy, but I wanted to give all details, actual question is in bold below.

I have defined an External content type, let's call it ExternalCustomer.

I use an ExternalCustomer-column in a doclib, so user can select an external customer to his document in a picker dialog.

I have used SPD to create the ECT and selected my WCF service method as my default reader method. Since there will be a huge number of External Customers I need to send an extra parameter to the method, a guid that is stored on the specific SPWeb where the doclib resides (and can be in the URL as well if needed).

The service signature looks like this

List<ExternalCustomer> GetExternalCustomers()

I want to change it to

List<ExternalCustomer> GetExternalCustomers(Guid regionId)  

and somehow sneak in that extra parameter somewhere so it reaches my service. I'm creating the docLib in code from a custom listdef during init of the SPWeb. I can edit the XML that defines the BDC.

I don't want user to input the Id (as a filter parameter), I would prefer to not get all customers and then filter 99% of them away.

(As a backup will have to define a custom field type with a custom picker, but i have more then one external content type...It seems very much work for this tiny extra functionality)

I run SP 2013, I have both the service provider and SP on my own servers.

Answer 1

I gave up on the thought of hijacking the picker dialog and went with client side custom fieldtypes, created a http-handler which uses the BDC API, where I can send the parameter needed. I then actually set the bdcfields in the event reciever. With this solution I can use comboboxes (or whatever I want) instead of the picker dialog.