The first step in fixing a group of problems related to outputting a proper

"value" for a field that is a relation to another model.

This part adds the utility method on Model that should help in general.Also
cleans up the slightly ugly mess from r8957.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9601 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/base.py

@@ -296,6 +296,16 @@ class Model(object):
 
     pk = property(_get_pk_val, _set_pk_val)
 
+    def serializable_value(self, field_name):
+        """
+        Returns the value of the field name for this instance. If the field
+        is a foreign key, returns the id value, instead of the object.
+        Used to serialize a field's value (in the serializer, or form output,
+        for example).
+        """
+        field = self._meta.get_field_by_name(field_name)[0]
+        return getattr(self, field.attname)
+
     def save(self, force_insert=False, force_update=False):
         """
         Saves the current instance. Override this in a subclass if you want to

django/db/models/options.py

@@ -448,3 +448,4 @@ class Options(object):
             #        objects.append(opts)
             self._ordered_objects = objects
         return self._ordered_objects
+

django/forms/models.py

@@ -624,13 +624,7 @@ class ModelChoiceIterator(object):
 
     def choice(self, obj):
         if self.field.to_field_name:
-            # FIXME: The try..except shouldn't be necessary here. But this is
+            key = obj.serializable_value(self.field.to_field_name)
-            # going in just before 1.0, so I want to be careful. Will check it
-            # out later.
-            try:
-                key = getattr(obj, self.field.to_field_name).pk
-            except AttributeError:
-                key = getattr(obj, self.field.to_field_name)
         else:
             key = obj.pk
         return (key, self.field.label_from_instance(obj))