Force field value if created from another action - odoo

Question

I have a model that inherits from "hr.employee" and I have an action that will
display only the employees which are in a special department.
I would like that the "Create" button on top of that list allows me to
create a record in hr.employee with the department field already set to that special department.
Of course the other "Create" button, from the standard "hr" module,
should not set a default value for the department.
Here's the model:
# -*- coding: utf-8 -*-
from openerp import models, fields
class Patient(models.Model):
_inherit = 'hr.employee'
date_debut_contrat = fields.Date('Début Contrat de Prise en Charge')
date_fin_contrat = fields.Date('Fin Contrat de Prise en Charge')
And here's the action:
<record id="action_liste_patients" model="ir.actions.act_window">
<field name="name">Patients</field>
<field name="res_model">hr.employee</field>
<field name="view_mode">kanban,tree,form</field>
<field name="domain">[('department_id.is_patients', '=', 'true')]</field>
</record>
Do I have a way to tell Odoo that from that action, the department_id field should have a default value, without changing the behaviour of the standard action ?
Many thanks to all.
Marc

Answer 1

You can use
<field name="context">{'department_id': 'special department'}</field>
Now while creating Patient, in create() you can fetch value from context and act accordingly.

Answer 2

Based on Jamin's comment, here's the full solution I applied:
1) Add a context to the action. The context will have a value named
"create_as_patient", which is True or False.
<record id="action_liste_patients" model="ir.actions.act_window">
<field name="name">Patients</field>
<field name="res_model">hr.employee</field>
<field name="view_mode">kanban,tree,form</field>
<field name="domain">[('department_id.is_patients', '=', 'true')]</field>
<field name="context">{'create_as_patient': True}</field>
</record>
2) In the create() method of my model, I fetch the value from the
context if it's present. Then I search in the "hr.department" model
for the department which is marked as default department for patients.
Then, if the default department has been found, I set the new record's
department_id to it.
# -*- coding: utf-8 -*-
from openerp import models, fields, api
class Patient(models.Model):
_inherit = 'hr.employee'
date_debut_contrat = fields.Date('Début Contrat de Prise en Charge')
date_fin_contrat = fields.Date('Fin Contrat de Prise en Charge')
#api.model
def create(self, vals):
if 'create_as_patient' in self.env.context:
if self.env.context['create_as_patient']:
departmentId = self.env['hr.department'].search([('is_patients', '=', True)], limit=1).id
if departmentId is not None:
vals['department_id'] = departmentId
record = super(Patient, self).create(vals)
return record
This meets my requirements :
From the Employee action, which doesn't have the 'create_as_patient'
flag in its context, newly created employees will not have the
default department set.
On the other hand, if I create a record from
my Patient action, the flag will be present, and the default
department will be added to the new record.
Many thanks again to jamin for pointing me the right direction :-)
Marc