class NullBooleanField
from django.forms import NullBooleanField
A field whose valid values are None, True, and False. Clean invalid values
to None.
Ancestors (MRO)
- NullBooleanField
- BooleanField
- Field
Methods
def
bound_data(self, data, initial):
¶
Field
Return the value that should be shown for this field on render of a
bound form, given the submitted POST data for the field and the initial
data, if any.
For most fields, this will simply be data; FileFields need to handle it
a bit differently.
def bound_data(self, data, initial):
"""
Return the value that should be shown for this field on render of a
bound form, given the submitted POST data for the field and the initial
data, if any.
For most fields, this will simply be data; FileFields need to handle it
a bit differently.
"""
if self.disabled:
return initial
return data
def
clean(self, value):
¶
Field
Validate the given value and return its "cleaned" value as an
appropriate Python object. Raise ValidationError for any errors.
def clean(self, value):
"""
Validate the given value and return its "cleaned" value as an
appropriate Python object. Raise ValidationError for any errors.
"""
value = self.to_python(value)
self.validate(value)
self.run_validators(value)
return value
def
get_bound_field(self, form, field_name):
¶
Field
Return a BoundField instance that will be used when accessing the form
field in a template.
def get_bound_field(self, form, field_name):
"""
Return a BoundField instance that will be used when accessing the form
field in a template.
"""
return BoundField(form, self, field_name)
def
has_changed(self, initial, data):
¶
BooleanField
def has_changed(self, initial, data):
if self.disabled:
return False
# Sometimes data or initial may be a string equivalent of a boolean
# so we should run it through to_python first to get a boolean value
return self.to_python(initial) != self.to_python(data)
Field
Return True if data differs from initial.
def has_changed(self, initial, data):
"""Return True if data differs from initial."""
# Always return False if the field is disabled since self.bound_data
# always uses the initial value in this case.
if self.disabled:
return False
try:
data = self.to_python(data)
if hasattr(self, '_coerce'):
return self._coerce(data) != self._coerce(initial)
except ValidationError:
return True
# For purposes of seeing whether something has changed, None is
# the same as an empty string, if the data or initial value we get
# is None, replace it with ''.
initial_value = initial if initial is not None else ''
data_value = data if data is not None else ''
return initial_value != data_value
def
prepare_value(self, value):
¶
Field
def prepare_value(self, value):
return value
def
run_validators(self, value):
¶
Field
def run_validators(self, value):
if value in self.empty_values:
return
errors = []
for v in self.validators:
try:
v(value)
except ValidationError as e:
if hasattr(e, 'code') and e.code in self.error_messages:
e.message = self.error_messages[e.code]
errors.extend(e.error_list)
if errors:
raise ValidationError(errors)
def
to_python(self, value):
¶
NullBooleanField
Explicitly check for the string 'True' and 'False', which is what a
hidden field will submit for True and False, for 'true' and 'false',
which are likely to be returned by JavaScript serializations of forms,
and for '1' and '0', which is what a RadioField will submit. Unlike
the Booleanfield, this field must check for True because it doesn't
use the bool() function.
def to_python(self, value):
"""
Explicitly check for the string 'True' and 'False', which is what a
hidden field will submit for True and False, for 'true' and 'false',
which are likely to be returned by JavaScript serializations of forms,
and for '1' and '0', which is what a RadioField will submit. Unlike
the Booleanfield, this field must check for True because it doesn't
use the bool() function.
"""
if value in (True, 'True', 'true', '1'):
return True
elif value in (False, 'False', 'false', '0'):
return False
else:
return None
BooleanField
Return a Python boolean object.
def to_python(self, value):
"""Return a Python boolean object."""
# Explicitly check for the string 'False', which is what a hidden field
# will submit for False. Also check for '0', since this is what
# RadioSelect will provide. Because bool("True") == bool('1') == True,
# we don't need to handle that explicitly.
if isinstance(value, str) and value.lower() in ('false', '0'):
value = False
else:
value = bool(value)
return super().to_python(value)
Field
def to_python(self, value):
return value
def
validate(self, value):
¶
NullBooleanField
def validate(self, value):
pass
BooleanField
def validate(self, value):
if not value and self.required:
raise ValidationError(self.error_messages['required'], code='required')
Field
def validate(self, value):
if value in self.empty_values and self.required:
raise ValidationError(self.error_messages['required'], code='required')
def
widget_attrs(self, widget):
¶
Field
Given a Widget instance (*not* a Widget class), return a dictionary of
any HTML attributes that should be added to the Widget, based on this
Field.
def widget_attrs(self, widget):
"""
Given a Widget instance (*not* a Widget class), return a dictionary of
any HTML attributes that should be added to the Widget, based on this
Field.
"""
return {}