Commit 535809e1 authored by Moritz Sichert's avatar Moritz Sichert Committed by Tim Graham
Browse files

Fixed #25294 -- Allowed custom BoundFields on forms.

parent 8615e415

django/forms/fields.py

+8 −0
Original line number Diff line number Diff line
@@ -204,6 +204,14 @@ class Field(six.with_metaclass(RenameFieldMethods, object)): 
        data_value = data if data is not None else ''

        return initial_value != data_value



    def get_bound_field(self, form, field_name):

        """

        Return a BoundField instance that will be used when accessing the form

        field in a template.

        """

        from django.forms.forms import BoundField

        return BoundField(form, self, field_name)



    def __deepcopy__(self, memo):

        result = copy.copy(self)

        memo[id(self)] = result

django/forms/forms.py

+1 −1
Original line number Diff line number Diff line
@@ -152,7 +152,7 @@ class BaseForm(object): 
            raise KeyError(

                "Key %r not found in '%s'" % (name, self.__class__.__name__))

        if name not in self._bound_fields_cache:

            self._bound_fields_cache[name] = BoundField(self, field, name)

            self._bound_fields_cache[name] = field.get_bound_field(self, name)

        return self._bound_fields_cache[name]



    @property

docs/ref/forms/api.txt

+42 −0
Original line number Diff line number Diff line
@@ -932,6 +932,48 @@ and using the template above, would render something like: 


    <label for="myFIELD">...</label><input id="myFIELD" type="text" name="my_field" />



Customizing ``BoundField``

--------------------------



.. versionadded:: 1.9



If you need to access some additional information about a form field in a

template and using a subclass of :class:`~django.forms.Field` isn't

sufficient, consider also customizing :class:`~django.forms.BoundField`.



A custom form field can override ``get_bound_field()``:



.. method:: Field.get_bound_field(form, field_name)



    Takes an instance of :class:`~django.forms.Form` and the name of the field.

    The return value will be used when accessing the field in a template. Most

    likely it will be an instance of a subclass of

    :class:`~django.forms.BoundField`.



If you have a ``GPSCoordinatesField``, for example, and want to be able to

access additional information about the coordinates in a template, this could

be implemented as follows::



    class GPSCoordinatesBoundField(BoundField):

        @property

        def country(self):

            """

            Return the country the coordinates lie in or None if it can't be

            determined.

            """

            value = self.value()

            if value:

                return get_country_from_coordinates(value)

            else:

                return None



    class GPSCoordinatesField(Field):

        def get_bound_field(self, form, field_name):

            return GPSCoordinatesBoundField(form, self, field_name)



Now you can access the country in a template with

``{{ form.coordinates.country }}``.



.. _binding-uploaded-files:



Binding uploaded files to a form

docs/ref/forms/fields.txt

+3 −0
Original line number Diff line number Diff line
@@ -1239,3 +1239,6 @@ custom ``Field`` classes. To do this, just create a subclass of 
``clean()`` method and that its ``__init__()`` method accept the core arguments

mentioned above (``required``, ``label``, ``initial``, ``widget``,

``help_text``).



You can also customize how a field will be accessed by overriding

:meth:`~django.forms.Field.get_bound_field()`.

docs/releases/1.9.txt

+3 −0
Original line number Diff line number Diff line
@@ -364,6 +364,9 @@ Forms 
* Form fields now support the :attr:`~django.forms.Field.disabled` argument,

  allowing the field widget to be displayed disabled by browsers.



* It's now possible to customize bound fields by overriding a field's

  :meth:`~django.forms.Field.get_bound_field()` method.



Generic Views

^^^^^^^^^^^^^