you can raise a warning message in on_change by

return {

    'warning': {

        'title': 'Warning!',

        'message': 'The warning text'}

}

and this question is already in community hear

Hi Try this in odoo16.

return {
        'warning': {'title': "Warning", 'message': "What is this?", 'type': 'notification'},
    }

If the type is set to notification, the warning will be displayed in a notification.
Otherwise, it will be displayed in a dialog as default.

Thanks

Gouranga Kala

You can try:

return {'value':{},'warning':{'title':'warning','message':'Your message'}}

Thanks

Hello friend;

here is how you can print a warning message.

First, you should import:

from openerp.osv.orm import except_orm

And then in your python:

My_error_Msg = 'hello!!'

raise osv.except_osv(_("Error!"), _(My_error_Msg))

return True

So that, there are two possibilities:

- if you want to block the access and the record (return True)

-Only print the warning message, press ok and save the record (return False)

Some useful links:

https://www.odoo.com/fr_FR/forum/help-1/question/using-raise-osv-except-osv-16015

http://odoo-new-api-guide-line.readthedocs.org/en/latest/conventions.html

http://stackoverflow.com/questions/29072343/how-to-display-openerp-error-message

http://stackoverflow.com/questions/30210715/how-to-create-a-function-to-raise-error-in-openerp

Best Regards.

Hello wizards,

You can use "raise Warning" instead of "raise osv.except_osv".

Thank you.