Changeset 7326

Timestamp:

03/19/08 18:10:45 (1 year ago)

Author:

jacob

Message:

Fixed #4620: you can now easily add custom labels to ModelChoiceFields? via subclassing. Thanks, PhiR.

Files:

• django/trunk/django/newforms/models.py (modified) (4 diffs)
• django/trunk/docs/newforms.txt (modified) (1 diff)
• django/trunk/tests/modeltests/model_forms/models.py (modified) (2 diffs)

django/trunk/django/newforms/models.py

@@ -278 +278 @@
-# Fields #####################################################################
-
-
-
-
-
-
+
+
+
+
-
-    def __iter__(self):
-
-
+field.
+field.
-        for obj in self.queryset:
-mart_unicod
+elf.field.label_from_instanc
-        # Clear the QuerySet cache if required.
-
+field.
-            self.queryset._result_cache = None
-
@@ -307 +306 @@
-        self.empty_label = empty_label
-        self.cache_choices = cache_choices
+        
-        # Call Field instead of ChoiceField __init__() because we don't need
-        # ChoiceField.__init__().
@@ -322 +322 @@
-    queryset = property(_get_queryset, _set_queryset)
-
+    # this method will be used to create object labels by the QuerySetIterator. 
+    # Override it to customize the label. 
+    def label_from_instance(self, obj):
+        """
+        This method is used to convert objects into strings; it's used to
+        generate the labels for the choices presented by this object. Subclasses
+        can override this method to customize the display of the choices.
+        """
+        return smart_unicode(obj)
+    
-    def _get_choices(self):
-        # If self._choices is set, then somebody must have manually set
@@ -327 +337 @@
-        if hasattr(self, '_choices'):
-            return self._choices
+
-        # Otherwise, execute the QuerySet in self.queryset to determine the
-
-been consumed. Note that we're instantiating a new QuerySetIterator
-*each* time _get_choices() is called (and, thus, each time
-self.choices is accessed) so that we can ensure the QuerySet has not
-been consumed.
-return QuerySetIterator(self.queryset, self.empty_label,
-                        self.cache_choices
+ been
+consumed. Note that we're instantiating a new QuerySetIterator *each*
+time _get_choices() is called (and, thus, each time self.choices is
+accessed) so that we can ensure the QuerySet has not been consumed. This
+construct might look complicated but it allows for lazy evaluation of
+# the queryset.
+return ModelChoiceIterator(self
-
-    def _set_choices(self, value):

django/trunk/docs/newforms.txt

@@ -1550 +1550 @@
-~~~~~~~~~~~~~~~~~~~~
-
-
-
+
+
+
+
+
+
+
+
+
+
-
-``ModelMultipleChoiceField``
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-
-
-
+ representing a
+
+
-
-Creating custom fields

django/trunk/tests/modeltests/model_forms/models.py

@@ -660 +660 @@
-ValidationError: [u'Select a valid choice. That choice is not one of the available choices.']
-
+# check that we can safely iterate choices repeatedly
+>>> gen_one = list(f.choices)
+>>> gen_two = f.choices
+>>> gen_one[2]
+(2L, u"It's a test")
+>>> list(gen_two)
+[(u'', u'---------'), (1L, u'Entertainment'), (2L, u"It's a test"), (3L, u'Third')]
+
+# check that we can override the label_from_instance method to print custom labels (#4620)
+>>> f.queryset = Category.objects.all()
+>>> f.label_from_instance = lambda obj: "category " + str(obj)
+>>> list(f.choices)
+[(u'', u'---------'), (1L, 'category Entertainment'), (2L, "category It's a test"), (3L, 'category Third'), (4L, 'category Fourth')]
-
-# ModelMultipleChoiceField ####################################################
@@ -745 +758 @@
-ValidationError: [u'Select a valid choice. 4 is not one of the available choices.']
-
+>>> f.queryset = Category.objects.all()
+>>> f.label_from_instance = lambda obj: "multicategory " + str(obj)
+>>> list(f.choices)
+[(1L, 'multicategory Entertainment'), (2L, "multicategory It's a test"), (3L, 'multicategory Third'), (4L, 'multicategory Fourth')]
-
-# PhoneNumberField ############################################################