这可能更像是一个面向对象的 Python 问题。但它来自我问过的关于 Django的这个问题。
所以@burhan 建议不要在我的 Django 模板中手动写出我的自定义<select>和<option>标签，我应该只使用自定义ModelChoiceField和forms.Select.
我当前继承ModelForm并创建了一个OrderCreateForm为我的模型调用的自定义表单Order，creator'squeryset是基于creator'suser_type的，因此我需要以某种方式将变量传递给自定义ModelForm以在自定义中使用ModelChoiceField。
所以我最终想要这样的东西
class OrderCreateForm(ModelForm):
class Meta :
model=Order
fields=('work_type', 'comment',)
def __init__(self):
# somehow get a variable called user_type
if user_type == 'foo':
queryset = User.objects.all()
else:
queryset = User.objects.filter(userprofle__user_type='bar')
creator = MyCustomField(queryset=queryset,
empty_label="Please select",
widget=forms.Select(attrs={'onchange':'some_ajax_function()'})
__init__我知道在类中创建参数__init__与ModelForm.__init__. 我也想调用我的自定义ModelForm类，例如form=OrderCreateForm(user_type='foo_bar'). 那有可能吗。
对不起，如果我的问题令人困惑，就像我说我是一个 OO 新手，我不太了解所有的术语和概念。
编辑：这是来自 Django 的一些源代码ModelForm：
class BaseForm(StrAndUnicode):
# This is the main implementation of all the Form logic. Note that this
# class is different than Form. See the comments by the Form class for more
# information. Any improvements to the form API should be made to *this*
# class, not to the Form class.
def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
initial=None, error_class=ErrorList, label_suffix=':',
empty_permitted=False):
class BaseModelForm(BaseForm):
def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
initial=None, error_class=ErrorList, label_suffix=':',
empty_permitted=False, instance=None):
opts = self._meta
if instance is None:
if opts.model is None:
raise ValueError('ModelForm has no model class specified.')
# if we didn't get an instance, instantiate a new one
self.instance = opts.model()
object_data = {}
else:
self.instance = instance
object_data = model_to_dict(instance, opts.fields, opts.exclude)
# if initial was provided, it should override the values from instance
if initial is not None:
object_data.update(initial)
# self._validate_unique will be set to True by BaseModelForm.clean().
# It is False by default so overriding self.clean() and failing to call
# super will stop validate_unique from being called.
self._validate_unique = False
super(BaseModelForm, self).__init__(data, files, auto_id, prefix, object_data,
error_class, label_suffix, empty_permitted)
def _update_errors(self, message_dict):
for k, v in message_dict.items():
if k != NON_FIELD_ERRORS:
self._errors.setdefault(k, self.error_class()).extend(v)
# Remove the data from the cleaned_data dict since it was invalid
if k in self.cleaned_data:
del self.cleaned_data[k]
if NON_FIELD_ERRORS in message_dict:
messages = message_dict[NON_FIELD_ERRORS]
self._errors.setdefault(NON_FIELD_ERRORS, self.error_class()).extend(messages)
def _get_validation_exclusions(self):
"""
For backwards-compatibility, several types of fields need to be
excluded from model validation. See the following tickets for
details: #12507, #12521, #12553
"""
exclude = []
# Build up a list of fields that should be excluded from model field
# validation and unique checks.
for f in self.instance._meta.fields:
field = f.name
# Exclude fields that aren't on the form. The developer may be
# adding these values to the model after form validation.
if field not in self.fields:
exclude.append(f.name)
# Don't perform model validation on fields that were defined
# manually on the form and excluded via the ModelForm's Meta
# class. See #12901.
elif self._meta.fields and field not in self._meta.fields:
exclude.append(f.name)
elif self._meta.exclude and field in self._meta.exclude:
exclude.append(f.name)
# Exclude fields that failed form validation. There's no need for
# the model fields to validate them as well.
elif field in self._errors.keys():
exclude.append(f.name)
# Exclude empty fields that are not required by the form, if the
# underlying model field is required. This keeps the model field
# from raising a required error. Note: don't exclude the field from
# validation if the model field allows blanks. If it does, the blank
# value may be included in a unique check, so cannot be excluded
# from validation.
else:
form_field = self.fields[field]
field_value = self.cleaned_data.get(field, None)
if not f.blank and not form_field.required and field_value in EMPTY_VALUES:
exclude.append(f.name)
return exclude
def clean(self):
self._validate_unique = True
return self.cleaned_data
def _post_clean(self):
opts = self._meta
# Update the model instance with self.cleaned_data.
self.instance = construct_instance(self, self.instance, opts.fields, opts.exclude)
exclude = self._get_validation_exclusions()
# Foreign Keys being used to represent inline relationships
# are excluded from basic field value validation. This is for two
# reasons: firstly, the value may not be supplied (#12507; the
# case of providing new values to the admin); secondly the
# object being referred to may not yet fully exist (#12749).
# However, these fields *must* be included in uniqueness checks,
# so this can't be part of _get_validation_exclusions().
for f_name, field in self.fields.items():
if isinstance(field, InlineForeignKeyField):
exclude.append(f_name)
# Clean the model instance's fields.
try:
self.instance.clean_fields(exclude=exclude)
except ValidationError, e:
self._update_errors(e.message_dict)
# Call the model instance's clean method.
try:
self.instance.clean()
except ValidationError, e:
self._update_errors({NON_FIELD_ERRORS: e.messages})
# Validate uniqueness if needed.
if self._validate_unique:
self.validate_unique()
def validate_unique(self):
"""
Calls the instance's validate_unique() method and updates the form's
validation errors if any were raised.
"""
exclude = self._get_validation_exclusions()
try:
self.instance.validate_unique(exclude=exclude)
except ValidationError, e:
self._update_errors(e.message_dict)
def save(self, commit=True):
"""
Saves this ``form``'s cleaned_data into model instance
``self.instance``.
If commit=True, then the changes to ``instance`` will be saved to the
database. Returns ``instance``.
"""
if self.instance.pk is None:
fail_message = 'created'
else:
fail_message = 'changed'
return save_instance(self, self.instance, self._meta.fields,
fail_message, commit, construct=False)
save.alters_data = True
class ModelForm(BaseModelForm):
__metaclass__ = ModelFormMetaclass