My case :

I have two fields :

1. partner_id : m2o (res.partner) type
2. type : selection(sale or purchase)

On a form view, I want when I set type=sale, the domain=[('customer','=',True)] applied to the field partner_id

My idea is to use onchange action on the field type, but I don't know how

on_change in OpenERP

1: The value dictionary i.e {field1:value1,field2:value2}

2: The domain dictionary i.e {field1:domain1}

3: The warning

Syntax:

res = {'value':{},'domain':{},'warning':'Warning Message'}

According to your case add this to the return dictionary.

{'domain':{'partner_id':[('customer','=',True)]}}

Thanks