Abdouerp, I think you need to provide more explanation.  From what I gather, you have a wizard that has a list view (which is most probably either a one2many or many2many field).  Now, I'm not clear where the dropdown list is and which fields value that you need to get.  To get the value of any fields in the one2many/many2many field you need to do something like:

_wizard_obj = self.browse(cr, uid, ids[0], context=context)

for _line in _wizard_obj.2many_fields_name:

    _field_value = _line.field_name_to_get