Thanks Paresh for your answer.
Infact it s a just filter a list of product depending of the choice of a field attached to another model (product_id on mrp.repair) and others parameters (filter the list if the category is accessorie or square part, stock available .... )  . 

Depending of the choice , a different request need to be executed (if the product_id on mrp.repair has bom_ids , i need to list only bods_ids products.

That s why i need to use a method . 
So I can t use domain=[()] on xml if think isn t it?

Also if the product_id on the mrp.repair change i need to refresh the list

I hope it s more clear for you . Don t hesitate if you have more questions :)

Cheers

Hi Thomas:

Did you mean "recompute" or just "filter" the list of product ids that the user can select ?

If it is just to filter the list of products, you can use a domain="[(....)]" attribute of the field in the view definition.