Referenced and Referencing Component Usages Must Address the Same Component

Question

Hi,
I have a main component MC and it has two used componenents - IBLC and IVAC (interfaces for model and visual compoenents).
I get the actual model component name from a table and I instantiate it as follows:
instantiate model component
DATA: l_ref_model_usage TYPE REF TO if_wd_component_usage,
l_my_initial_usage type ref to IF_WD_COMPONENT_USAGE.
L_MY_INITIAL_USAGE = wd_this->wd_cpuse_iblc( ).
l_ref_model_usage = L_MY_INITIAL_USAGE->CREATE_COMP_USAGE_OF_SAME_TYPE(
NAME = Item_Modelcomp ).
Components VC1 and VC2 etc implement IVAC.
Since I want to use the same instance of Item_Modelcomp in VC1 and VC2, I use the set_model(and from that I call method enter_referencing_mode) method as follows in MC.
l_ref_interfacecontroller->set_model( model_usage = l_ref_model_usage ).
Now in set_model method in VC1, I am using Item_Modelcomp as used component and not IBLC because I want to use the Item_Modelcomp context, but it expects IBLC as the used component(even though Item_Modelcomp implements IBLC) and hence gives the error "Referenced and Referencing Component Usages Must Address the Same Component".
Any solution for this issue?
Thanks and Regards,
Srini.

Answer 1

Hi Srinivasa,
>I thought model compoenents are the ideal way to share
>context across different visual components.
Yeah, we though the same in the beginning. Later on we learned that:
  - it's not worth having the overhead of another WD component in most cases since you need to call the business logic nonetheless
  - declaring nodes as public is like having public attributes at a class - which can be really bad thing
  - there are lots of side effects regarding one component affecting the other one indirectly by having both mapped to the same model component
In general, using model components should be avoided. There might be rare cases, where it makes sense to use them, but mostly it's not worth the effort.
Best regards,
Thomas