Field(**kwargs)¶Form クラスを作成時の一番重要な部分は、form のフィールド (field) の定義です。各フィールドにはカスタムの検証ロジックがあり、他にいくつかのフックもあります。
Field.clean(value)¶Although the primary way you'll use Field classes is in Form classes,
you can also instantiate them and use them directly to get a better idea of
how they work. Each Field instance has a clean() method, which takes
a single argument and either raises a
django.core.exceptions.ValidationError exception or returns the clean
value:
>>> from django import forms
>>> f = forms.EmailField()
>>> f.clean('foo@example.com')
'foo@example.com'
>>> f.clean('invalid email address')
Traceback (most recent call last):
...
ValidationError: ['Enter a valid email address.']
各 Field クラスのコンストラクタは少なくとも以下の引数を受け付けます。Field クラスによっては追加のフィールド固有の引数も取れることがありますが、以下に説明する引数は 常に 取ることができます。
required¶Field.required¶By default, each Field class assumes the value is required, so if you pass
an empty value -- either None or the empty string ("") -- then
clean() will raise a ValidationError exception:
>>> from django import forms
>>> f = forms.CharField()
>>> f.clean('foo')
'foo'
>>> f.clean('')
Traceback (most recent call last):
...
ValidationError: ['This field is required.']
>>> f.clean(None)
Traceback (most recent call last):
...
ValidationError: ['This field is required.']
>>> f.clean(' ')
' '
>>> f.clean(0)
'0'
>>> f.clean(True)
'True'
>>> f.clean(False)
'False'
To specify that a field is not required, pass required=False to the
Field constructor:
>>> f = forms.CharField(required=False)
>>> f.clean('foo')
'foo'
>>> f.clean('')
''
>>> f.clean(None)
''
>>> f.clean(0)
'0'
>>> f.clean(True)
'True'
>>> f.clean(False)
'False'
If a Field has required=False and you pass clean() an empty value,
then clean() will return a normalized empty value rather than raising
ValidationError. For CharField, this will return
empty_value which defaults to an empty string. For other
Field classes, it might be None. (This varies from field to field.)
Widgets of required form fields have the required HTML attribute. Set the
Form.use_required_attribute attribute to False to disable it. The
required attribute isn't included on forms of formsets because the browser
validation may not be correct when adding and deleting formsets.
label¶Field.label¶label 属性は、フィールドに対する "人が読みやすい" ラベルを指定します。このラベルは Field が Form 内で表示されるときに使用されます。
上述の "HTML としてフォームを出力する" で説明したとおり、Field に対するデフォルトのラベルはアンダースコアを空白に、また単語の最初の小文字を大文字に変換して生成されます。 デフォルトではない文字列を表示したい場合には、label を指定してください。
以下は、label を 2 つのフィールドに実装した Form の実例です。出力を見やすくするため auto_id=False を指定しています。
>>> from django import forms
>>> class CommentForm(forms.Form):
... name = forms.CharField(label='Your name')
... url = forms.URLField(label='Your website', required=False)
... comment = forms.CharField()
>>> f = CommentForm(auto_id=False)
>>> print(f)
<tr><th>Your name:</th><td><input type="text" name="name" required></td></tr>
<tr><th>Your website:</th><td><input type="url" name="url"></td></tr>
<tr><th>Comment:</th><td><input type="text" name="comment" required></td></tr>
label_suffix¶Field.label_suffix¶label_suffix 属性は、フィールドごとの label_suffix をオーバーライドします:
>>> class ContactForm(forms.Form):
... age = forms.IntegerField()
... nationality = forms.CharField()
... captcha_answer = forms.IntegerField(label='2 + 2', label_suffix=' =')
>>> f = ContactForm(label_suffix='?')
>>> print(f.as_p())
<p><label for="id_age">Age?</label> <input id="id_age" name="age" type="number" required></p>
<p><label for="id_nationality">Nationality?</label> <input id="id_nationality" name="nationality" type="text" required></p>
<p><label for="id_captcha_answer">2 + 2 =</label> <input id="id_captcha_answer" name="captcha_answer" type="number" required></p>
initial¶Field.initial¶initial 属性は、Field が結びつけられていない Form で表示されるときに使われる初期値を指定します。
動的に初期値を指定する方法は、Form.initial パラメータを参照してください。
The use-case for this is when you want to display an "empty" form in which a field is initialized to a particular value. For example:
>>> from django import forms
>>> class CommentForm(forms.Form):
... name = forms.CharField(initial='Your name')
... url = forms.URLField(initial='http://')
... comment = forms.CharField()
>>> f = CommentForm(auto_id=False)
>>> print(f)
<tr><th>Name:</th><td><input type="text" name="name" value="Your name" required></td></tr>
<tr><th>Url:</th><td><input type="url" name="url" value="http://" required></td></tr>
<tr><th>Comment:</th><td><input type="text" name="comment" required></td></tr>
You may be thinking, why not just pass a dictionary of the initial values as data when displaying the form? Well, if you do that, you'll trigger validation, and the HTML output will include any validation errors:
>>> class CommentForm(forms.Form):
... name = forms.CharField()
... url = forms.URLField()
... comment = forms.CharField()
>>> default_data = {'name': 'Your name', 'url': 'http://'}
>>> f = CommentForm(default_data, auto_id=False)
>>> print(f)
<tr><th>Name:</th><td><input type="text" name="name" value="Your name" required></td></tr>
<tr><th>Url:</th><td><ul class="errorlist"><li>Enter a valid URL.</li></ul><input type="url" name="url" value="http://" required></td></tr>
<tr><th>Comment:</th><td><ul class="errorlist"><li>This field is required.</li></ul><input type="text" name="comment" required></td></tr>
This is why initial values are only displayed for unbound forms. For bound
forms, the HTML output will use the bound data.
Also note that initial values are not used as "fallback" data in
validation if a particular field's value is not given. initial values are
only intended for initial form display:
>>> class CommentForm(forms.Form):
... name = forms.CharField(initial='Your name')
... url = forms.URLField(initial='http://')
... comment = forms.CharField()
>>> data = {'name': '', 'url': '', 'comment': 'Foo'}
>>> f = CommentForm(data)
>>> f.is_valid()
False
# The form does *not* fall back to using the initial values.
>>> f.errors
{'url': ['This field is required.'], 'name': ['This field is required.']}
Instead of a constant, you can also pass any callable:
>>> import datetime
>>> class DateForm(forms.Form):
... day = forms.DateField(initial=datetime.date.today)
>>> print(DateForm())
<tr><th>Day:</th><td><input type="text" name="day" value="12/23/2008" required><td></tr>
The callable will be evaluated only when the unbound form is displayed, not when it is defined.
help_text¶Field.help_text¶help_text 引数は、Field を説明するテキストを指定します。help_text を指定した場合、容易な Form メソッド (例えば as_ul()) で Field がレンダリングされるときに、Field の隣に表示されます。
モデルフィールドの help_text と同じく、値は自動的に生成されるフォーム内で HTML 用にエスケープされません。
Here's a full example Form that implements help_text for two of its
fields. We've specified auto_id=False to simplify the output:
>>> from django import forms
>>> class HelpTextContactForm(forms.Form):
... subject = forms.CharField(max_length=100, help_text='100 characters max.')
... message = forms.CharField()
... sender = forms.EmailField(help_text='A valid email address, please.')
... cc_myself = forms.BooleanField(required=False)
>>> f = HelpTextContactForm(auto_id=False)
>>> print(f.as_table())
<tr><th>Subject:</th><td><input type="text" name="subject" maxlength="100" required><br><span class="helptext">100 characters max.</span></td></tr>
<tr><th>Message:</th><td><input type="text" name="message" required></td></tr>
<tr><th>Sender:</th><td><input type="email" name="sender" required><br>A valid email address, please.</td></tr>
<tr><th>Cc myself:</th><td><input type="checkbox" name="cc_myself"></td></tr>
>>> print(f.as_ul()))
<li>Subject: <input type="text" name="subject" maxlength="100" required> <span class="helptext">100 characters max.</span></li>
<li>Message: <input type="text" name="message" required></li>
<li>Sender: <input type="email" name="sender" required> A valid email address, please.</li>
<li>Cc myself: <input type="checkbox" name="cc_myself"></li>
>>> print(f.as_p())
<p>Subject: <input type="text" name="subject" maxlength="100" required> <span class="helptext">100 characters max.</span></p>
<p>Message: <input type="text" name="message" required></p>
<p>Sender: <input type="email" name="sender" required> A valid email address, please.</p>
<p>Cc myself: <input type="checkbox" name="cc_myself"></p>
error_messages¶Field.error_messages¶The error_messages argument lets you override the default messages that the
field will raise. Pass in a dictionary with keys matching the error messages you
want to override. For example, here is the default error message:
>>> from django import forms
>>> generic = forms.CharField()
>>> generic.clean('')
Traceback (most recent call last):
...
ValidationError: ['This field is required.']
And here is a custom error message:
>>> name = forms.CharField(error_messages={'required': 'Please enter your name'})
>>> name.clean('')
Traceback (most recent call last):
...
ValidationError: ['Please enter your name']
In the built-in Field classes section below, each Field defines the
error message keys it uses.
validators¶Field.validators¶validators 引数は、フィールドに対するバリデーション関数のリストを指定します。
詳しくは validators documentation を参照してください。
localize¶Field.localize¶localize 引数は、form データの入力とレンダリングした出力のローカライゼーションを有効にします。
詳しくは 書式のローカライゼーション ドキュメントを読んでください。
has_changed()¶Field.has_changed()¶has_changed() メソッドは、フィールドの値が最初の値から変更されたかどうかを確認するのに使用します。True または False を返します。
詳しくは Form.has_changed() ドキュメントを読んでください。
Field クラス¶Naturally, the forms library comes with a set of Field classes that
represent common validation needs. This section documents each built-in field.
For each field, we describe the default widget used if you don't specify
widget. We also specify the value returned when you provide an empty value
(see the section on required above to understand what that means).
BooleanField¶BooleanField(**kwargs)¶CheckboxInputFalseTrue or False value.True (e.g. the check box is checked) if
the field has required=True.required注釈
Since all Field subclasses have required=True by default, the
validation condition here is important. If you want to include a boolean
in your form that can be either True or False (e.g. a checked or
unchecked checkbox), you must remember to pass in required=False when
creating the BooleanField.
CharField¶CharField(**kwargs)¶TextInputempty_value として与えたものMaxLengthValidator and
MinLengthValidator if max_length and
min_length are provided. Otherwise, all inputs are valid.required, max_length, min_lengthHas four optional arguments for validation:
max_length¶min_length¶If provided, these arguments ensure that the string is at most or at least the given length.
strip¶If True (default), the value will be stripped of leading and
trailing whitespace.
empty_value¶The value to use to represent "empty". Defaults to an empty string.
ChoiceField¶ChoiceField(**kwargs)¶Select'' (空の文字列)required, invalid_choiceThe invalid_choice error message may contain %(value)s, which will be
replaced with the selected choice.
Takes one extra argument:
choices¶Either an iterable of 2-tuples to use as choices for this
field, enumeration choices, or a
callable that returns such an iterable. This argument accepts the same
formats as the choices argument to a model field. See the
model field reference documentation on choices
for more details. If the argument is a callable, it is evaluated each
time the field's form is initialized, in addition to during rendering.
Defaults to an empty list.
DateField¶DateField(**kwargs)¶DateInputNonedatetime.date オブジェクトに正規化されます。datetime.date、datetime.datetime または特定の日付の表示形式のどれかに当てはまるか検証します。required、invalid1 つの省略可能な引数を取ります:
input_formats¶文字列を有効な datetime.date オブジェクトに変換する試行に使う表示形式のリストです。
If no input_formats argument is provided, the default input formats are
taken from DATE_INPUT_FORMATS if USE_L10N is
False, or from the active locale format DATE_INPUT_FORMATS key if
localization is enabled. See also format localization.
DateTimeField¶DateTimeField(**kwargs)¶DateTimeInputNonedatetime.datetime オブジェクトに正規化されます。datetime.datetime、datetime.date または特定の日時の表示形式の文字列のどれかに当てはまるか検証します。required、invalid1 つの省略可能な引数を取ります:
input_formats¶A list of formats used to attempt to convert a string to a valid
datetime.datetime object, in addition to ISO 8601 formats.
The field always accepts strings in ISO 8601 formatted dates or similar
recognized by parse_datetime(). Some examples
are:
* '2006-10-25 14:30:59'
* '2006-10-25T14:30:59'
* '2006-10-25 14:30'
* '2006-10-25T14:30'
* '2006-10-25T14:30Z'
* '2006-10-25T14:30+02:00'
* '2006-10-25'
If no input_formats argument is provided, the default input formats are
taken from DATETIME_INPUT_FORMATS and
DATE_INPUT_FORMATS if USE_L10N is False, or from
the active locale format DATETIME_INPUT_FORMATS and
DATE_INPUT_FORMATS keys if localization is enabled. See also
format localization.
DecimalField¶DecimalField(**kwargs)¶Field.localize が False のとき NumberInput、True のとき TextInput.Nonedecimal に正規化されます。MaxValueValidator and
MinValueValidator if max_value and
min_value are provided. Leading and trailing whitespace is ignored.required, invalid, max_value,
min_value, max_digits, max_decimal_places,
max_whole_digitsThe max_value and min_value error messages may contain
%(limit_value)s, which will be substituted by the appropriate limit.
Similarly, the max_digits, max_decimal_places and
max_whole_digits error messages may contain %(max)s.
Takes four optional arguments:
max_value¶min_value¶These control the range of values permitted in the field, and should be
given as decimal.Decimal values.
max_digits¶The maximum number of digits (those before the decimal point plus those after the decimal point, with leading zeros stripped) permitted in the value.
decimal_places¶The maximum number of decimal places permitted.
DurationField¶DurationField(**kwargs)¶TextInputNonetimedelta に正規化されます。timedelta. The value must be between datetime.timedelta.min
and datetime.timedelta.max.required, invalid, overflow.Accepts any format understood by
parse_duration().
EmailField¶EmailField(**kwargs)¶EmailInputempty_value.EmailValidator to validate that
the given value is a valid email address, using a moderately complex
regular expression.required、invalidHas three optional arguments max_length, min_length, and
empty_value which work just as they do for CharField.
FileField¶FileField(**kwargs)¶ClearableFileInputNoneUploadedFile オブジェクトに正規化されます。required, invalid, missing, empty,
max_lengthHas two optional arguments for validation, max_length and
allow_empty_file. If provided, these ensure that the file name is at
most the given length, and that validation will succeed even if the file
content is empty.
UploadedFile オブジェクトについて詳しく知るには、 ファイルのアップロードのドキュメント を読んでください。
フォーム内で FileField を使用する時は、ファイルのデータをフォームにバインディング することも必要です。
The max_length error refers to the length of the filename. In the error
message for that key, %(max)d will be replaced with the maximum filename
length and %(length)d will be replaced with the current filename length.
FilePathField¶FilePathField(**kwargs)¶Select'' (空の文字列)required, invalid_choiceThe field allows choosing from files inside a certain directory. It takes five
extra arguments; only path is required:
path¶The absolute path to the directory whose contents you want listed. This directory must exist.
recursive¶If False (the default) only the direct contents of path will be
offered as choices. If True, the directory will be descended into
recursively and all descendants will be listed as choices.
match¶A regular expression pattern; only files with names matching this expression will be allowed as choices.
allow_files¶Optional. Either True or False. Default is True. Specifies
whether files in the specified location should be included. Either this or
allow_folders must be True.
allow_folders¶Optional. Either True or False. Default is False. Specifies
whether folders in the specified location should be included. Either this or
allow_files must be True.
FloatField¶FloatField(**kwargs)¶Field.localize が False のとき NumberInput、True のとき TextInput.NoneMaxValueValidator and
MinValueValidator if max_value and
min_value are provided. Leading and trailing whitespace is allowed,
as in Python's float() function.required, invalid, max_value,
min_valueTakes two optional arguments for validation, max_value and min_value.
These control the range of values permitted in the field.
GenericIPAddressField¶GenericIPAddressField(**kwargs)¶IPv4 または IPv6 アドレスのいずれかを持つフィールドです。
TextInput'' (空の文字列)required、invalidIPv6 アドレスは、 RFC 4291#section-2.2 section 2.2 (同セクションの paragraph 3 で提案された IPv4 のフォーマットの使用を含む) にしたがって、 ::ffff:192.0.2.0 のように正規化します。たとえば、 2001:0::0:01 は 2001::1 と正規化され、 ::ffff:0a0a:0a0a は ::ffff:10.10.10.10 と正規化されます。そして、すべての文字は小文字に変換されます。
次の2つの省略可能な引数を取ります:
protocol¶有効な入力を指定したプロトコルに限定します。指定できる値は、 both (デフォルト)、 IPv4 または IPv6 です。大文字・小文字は無視されます。
unpack_ipv4¶IPv4 にマッピングされた ::ffff:192.0.2.1 のようなアドレスをアンパックします。このオプションを有効にすると、このアドレスは 192.0.2.1 とアンパックされます。デフォルトは無効です。protocol が 'both' に設定されている場合にだけ使用できます。
ImageField¶ImageField(**kwargs)¶ClearableFileInputNoneUploadedFile オブジェクトに正規化されます。FileExtensionValidator to validate that
the file extension is supported by Pillow.required, invalid, missing, empty,
invalid_imageUsing an ImageField requires that Pillow is installed with support
for the image formats you use. If you encounter a corrupt image error
when you upload an image, it usually means that Pillow doesn't understand
its format. To fix this, install the appropriate library and reinstall
Pillow.
When you use an ImageField on a form, you must also remember to
bind the file data to the form.
After the field has been cleaned and validated, the UploadedFile
object will have an additional image attribute containing the Pillow
Image instance used to check if the file was a valid image. Pillow
closes the underlying file descriptor after verifying an image, so while
non-image data attributes, such as format, height, and width,
are available, methods that access the underlying image data, such as
getdata() or getpixel(), cannot be used without reopening the file.
For example:
>>> from PIL import Image
>>> from django import forms
>>> from django.core.files.uploadedfile import SimpleUploadedFile
>>> class ImageForm(forms.Form):
... img = forms.ImageField()
>>> file_data = {'img': SimpleUploadedFile('test.png', <file data>)}
>>> form = ImageForm({}, file_data)
# Pillow closes the underlying file descriptor.
>>> form.is_valid()
True
>>> image_field = form.cleaned_data['img']
>>> image_field.image
<PIL.PngImagePlugin.PngImageFile image mode=RGBA size=191x287 at 0x7F5985045C18>
>>> image_field.image.width
191
>>> image_field.image.height
287
>>> image_field.image.format
'PNG'
>>> image_field.image.getdata()
# Raises AttributeError: 'NoneType' object has no attribute 'seek'.
>>> image = Image.open(image_field)
>>> image.getdata()
<ImagingCore object at 0x7f5984f874b0>
Additionally, UploadedFile.content_type will be updated with the
image's content type if Pillow can determine it, otherwise it will be set
to None.
IntegerField¶IntegerField(**kwargs)¶Field.localize が False のとき NumberInput、True のとき TextInput.NoneMaxValueValidator and
MinValueValidator if max_value and
min_value are provided. Leading and trailing whitespace is allowed,
as in Python's int() function.required, invalid, max_value,
min_valueThe max_value and min_value error messages may contain
%(limit_value)s, which will be substituted by the appropriate limit.
Takes two optional arguments for validation:
max_value¶min_value¶These control the range of values permitted in the field.
JSONField¶JSONField(encoder=None, decoder=None, **kwargs)¶A field which accepts JSON encoded data for a
JSONField.
TextareaNonedict, list, or None), depending on JSONField.decoder.required、invalid次の2つの省略可能な引数を取ります:
encoder¶A json.JSONEncoder subclass to serialize data types not
supported by the standard JSON serializer (e.g. datetime.datetime
or UUID). For example, you can use the
DjangoJSONEncoder class.
Defaults to json.JSONEncoder.
decoder¶A json.JSONDecoder subclass to deserialize the input. Your
deserialization may need to account for the fact that you can't be
certain of the input type. For example, you run the risk of returning a
datetime that was actually a string that just happened to be in the
same format chosen for datetimes.
The decoder can be used to validate the input. If
json.JSONDecodeError is raised during the deserialization,
a ValidationError will be raised.
Defaults to json.JSONDecoder.
User friendly forms
JSONField is not particularly user friendly in most cases. However,
it is a useful way to format data from a client-side widget for
submission to the server.
MultipleChoiceField¶MultipleChoiceField(**kwargs)¶SelectMultiple[] (空のリスト)required, invalid_choice, invalid_listThe invalid_choice error message may contain %(value)s, which will be
replaced with the selected choice.
Takes one extra required argument, choices, as for ChoiceField.
NullBooleanField¶NullBooleanField(**kwargs)¶NullBooleanSelectNoneTrue, False or None value.ValidationError).NullBooleanField may be used with widgets such as
Select or RadioSelect
by providing the widget choices:
NullBooleanField(
widget=Select(
choices=[
('', 'Unknown'),
(True, 'Yes'),
(False, 'No'),
]
)
)
RegexField¶RegexField(**kwargs)¶TextInputempty_value.RegexValidator to validate that
the given value matches a certain regular expression.required、invalidTakes one required argument:
regex¶A regular expression specified either as a string or a compiled regular expression object.
Also takes max_length, min_length, strip, and empty_value
which work just as they do for CharField.
strip¶Defaults to False. If enabled, stripping will be applied before the
regex validation.
SlugField¶SlugField(**kwargs)¶TextInputempty_value として与えたものvalidate_slug or
validate_unicode_slug to validate that
the given value contains only letters, numbers, underscores, and hyphens.required, invalidThis field is intended for use in representing a model
SlugField in forms.
Takes two optional parameters:
allow_unicode¶A boolean instructing the field to accept Unicode letters in addition
to ASCII letters. Defaults to False.
empty_value¶The value to use to represent "empty". Defaults to an empty string.
TimeField¶TimeField(**kwargs)¶TimeInputNonedatetime.time オブジェクトに正規化されます。datetime.time or string
formatted in a particular time format.required、invalid1 つの省略可能な引数を取ります:
input_formats¶A list of formats used to attempt to convert a string to a valid
datetime.time object.
If no input_formats argument is provided, the default input formats are
taken from TIME_INPUT_FORMATS if USE_L10N is
False, or from the active locale format TIME_INPUT_FORMATS key if
localization is enabled. See also format localization.
TypedChoiceField¶TypedChoiceField(**kwargs)¶Just like a ChoiceField, except TypedChoiceField takes two
extra arguments, coerce and empty_value.
Selectempty_value として与えたものcoerce
argument.required, invalid_choiceTakes extra arguments:
coerce¶A function that takes one argument and returns a coerced value. Examples
include the built-in int, float, bool and other types. Defaults
to an identity function. Note that coercion happens after input
validation, so it is possible to coerce to a value not present in
choices.
empty_value¶The value to use to represent "empty." Defaults to the empty string;
None is another common choice here. Note that this value will not be
coerced by the function given in the coerce argument, so choose it
accordingly.
TypedMultipleChoiceField¶TypedMultipleChoiceField(**kwargs)¶Just like a MultipleChoiceField, except TypedMultipleChoiceField
takes two extra arguments, coerce and empty_value.
SelectMultipleempty_value として渡したものcoerce
argument.required, invalid_choiceThe invalid_choice error message may contain %(value)s, which will be
replaced with the selected choice.
Takes two extra arguments, coerce and empty_value, as for
TypedChoiceField.
URLField¶URLField(**kwargs)¶URLInputempty_value.URLValidator to validate that the
given value is a valid URL.required、invalidHas three optional arguments max_length, min_length, and
empty_value which work just as they do for CharField.
Field classes¶ComboField¶ComboField(**kwargs)¶TextInput'' (空の文字列)ComboField.required、invalidTakes one extra required argument:
fields¶The list of fields that should be used to validate the field's value (in the order in which they are provided).
>>> from django.forms import ComboField
>>> f = ComboField(fields=[CharField(max_length=20), EmailField()])
>>> f.clean('test@example.com')
'test@example.com'
>>> f.clean('longemailaddress@example.com')
Traceback (most recent call last):
...
ValidationError: ['Ensure this value has at most 20 characters (it has 28).']
MultiValueField¶MultiValueField(fields=(), **kwargs)¶TextInput'' (空の文字列)compress method of the subclass.MultiValueField.required, invalid, incompleteAggregates the logic of multiple fields that together produce a single value.
This field is abstract and must be subclassed. In contrast with the
single-value fields, subclasses of MultiValueField must not
implement clean() but instead - implement
compress().
Takes one extra required argument:
fields¶A tuple of fields whose values are cleaned and subsequently combined
into a single value. Each value of the field is cleaned by the
corresponding field in fields -- the first value is cleaned by the
first field, the second value is cleaned by the second field, etc.
Once all fields are cleaned, the list of clean values is combined into
a single value by compress().
Also takes some optional arguments:
require_all_fields¶Defaults to True, in which case a required validation error
will be raised if no value is supplied for any field.
When set to False, the Field.required attribute can be set
to False for individual fields to make them optional. If no value
is supplied for a required field, an incomplete validation error
will be raised.
A default incomplete error message can be defined on the
MultiValueField subclass, or different messages can be defined
on each individual field. For example:
from django.core.validators import RegexValidator
class PhoneField(MultiValueField):
def __init__(self, **kwargs):
# Define one message for all fields.
error_messages = {
'incomplete': 'Enter a country calling code and a phone number.',
}
# Or define a different message for each field.
fields = (
CharField(
error_messages={'incomplete': 'Enter a country calling code.'},
validators=[
RegexValidator(r'^[0-9]+$', 'Enter a valid country calling code.'),
],
),
CharField(
error_messages={'incomplete': 'Enter a phone number.'},
validators=[RegexValidator(r'^[0-9]+$', 'Enter a valid phone number.')],
),
CharField(
validators=[RegexValidator(r'^[0-9]+$', 'Enter a valid extension.')],
required=False,
),
)
super().__init__(
error_messages=error_messages, fields=fields,
require_all_fields=False, **kwargs
)
widget¶Must be a subclass of django.forms.MultiWidget.
Default value is TextInput, which
probably is not very useful in this case.
compress(data_list)¶Takes a list of valid values and returns a "compressed" version of
those values -- in a single value. For example,
SplitDateTimeField is a subclass which combines a time field
and a date field into a datetime object.
This method must be implemented in the subclasses.
SplitDateTimeField¶SplitDateTimeField(**kwargs)¶SplitDateTimeWidgetNonedatetime.datetime オブジェクトに正規化されます。datetime.datetime or string
formatted in a particular datetime format.required, invalid, invalid_date,
invalid_time次の2つの省略可能な引数を取ります:
input_date_formats¶文字列を有効な datetime.date オブジェクトに変換する試行に使う表示形式のリストです。
If no input_date_formats argument is provided, the default input formats
for DateField are used.
input_time_formats¶A list of formats used to attempt to convert a string to a valid
datetime.time object.
If no input_time_formats argument is provided, the default input formats
for TimeField are used.
Two fields are available for representing relationships between
models: ModelChoiceField and
ModelMultipleChoiceField. Both of these fields require a
single queryset parameter that is used to create the choices for
the field. Upon form validation, these fields will place either one
model object (in the case of ModelChoiceField) or multiple model
objects (in the case of ModelMultipleChoiceField) into the
cleaned_data dictionary of the form.
For more complex uses, you can specify queryset=None when declaring the
form field and then populate the queryset in the form's __init__()
method:
class FooMultipleChoiceForm(forms.Form):
foo_select = forms.ModelMultipleChoiceField(queryset=None)
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.fields['foo_select'].queryset = ...
Both ModelChoiceField and ModelMultipleChoiceField have an iterator
attribute which specifies the class used to iterate over the queryset when
generating choices. See Iterating relationship choices for details.
ModelChoiceField¶ModelChoiceField(**kwargs)¶SelectNonerequired, invalid_choiceThe invalid_choice error message may contain %(value)s, which will
be replaced with the selected choice.
Allows the selection of a single model object, suitable for representing a
foreign key. Note that the default widget for ModelChoiceField becomes
impractical when the number of entries increases. You should avoid using it
for more than 100 items.
A single argument is required:
queryset¶A QuerySet of model objects from which the choices for the field
are derived and which is used to validate the user's selection. It's
evaluated when the form is rendered.
ModelChoiceField also takes several optional arguments:
empty_label¶By default the <select> widget used by ModelChoiceField will have an
empty choice at the top of the list. You can change the text of this
label (which is "---------" by default) with the empty_label
attribute, or you can disable the empty label entirely by setting
empty_label to None:
# A custom empty label
field1 = forms.ModelChoiceField(queryset=..., empty_label="(Nothing)")
# No empty label
field2 = forms.ModelChoiceField(queryset=..., empty_label=None)
Note that no empty choice is created (regardless of the value of
empty_label) if a ModelChoiceField is required and has a
default initial value, or a widget is set to
RadioSelect and the
blank argument is False.
to_field_name¶This optional argument is used to specify the field to use as the value
of the choices in the field's widget. Be sure it's a unique field for
the model, otherwise the selected value could match more than one
object. By default it is set to None, in which case the primary key
of each object will be used. For example:
# No custom to_field_name
field1 = forms.ModelChoiceField(queryset=...)
would yield:
<select id="id_field1" name="field1">
<option value="obj1.pk">Object1</option>
<option value="obj2.pk">Object2</option>
...
</select>
and:
# to_field_name provided
field2 = forms.ModelChoiceField(queryset=..., to_field_name="name")
would yield:
<select id="id_field2" name="field2">
<option value="obj1.name">Object1</option>
<option value="obj2.name">Object2</option>
...
</select>
blank¶When using the RadioSelect widget, this optional
boolean argument determines whether an empty choice is created. By
default, blank is False, in which case no empty choice is
created.
ModelChoiceField also has the attribute:
iterator¶The iterator class used to generate field choices from queryset. By
default, ModelChoiceIterator.
The __str__() method of the model will be called to generate string
representations of the objects for use in the field's choices. To provide
customized representations, subclass ModelChoiceField and override
label_from_instance. This method will receive a model object and should
return a string suitable for representing it. For example:
from django.forms import ModelChoiceField
class MyModelChoiceField(ModelChoiceField):
def label_from_instance(self, obj):
return "My Object #%i" % obj.id
Support for containing %(value)s in the invalid_choice error
message was added.
ModelMultipleChoiceField¶ModelMultipleChoiceField(**kwargs)¶SelectMultipleQuerySet (self.queryset.none())QuerySet of model instances.required, invalid_list, invalid_choice,
invalid_pk_valueThe invalid_choice message may contain %(value)s and the
invalid_pk_value message may contain %(pk)s, which will be
substituted by the appropriate values.
Allows the selection of one or more model objects, suitable for
representing a many-to-many relation. As with ModelChoiceField,
you can use label_from_instance to customize the object
representations.
A single argument is required:
queryset¶Same as ModelChoiceField.queryset.
1 つの省略可能な引数を取ります:
to_field_name¶Same as ModelChoiceField.to_field_name.
ModelMultipleChoiceField also has the attribute:
iterator¶Same as ModelChoiceField.iterator.
By default, ModelChoiceField and ModelMultipleChoiceField use
ModelChoiceIterator to generate their field choices.
When iterated, ModelChoiceIterator yields 2-tuple choices containing
ModelChoiceIteratorValue instances as the first value element in
each choice. ModelChoiceIteratorValue wraps the choice value while
maintaining a reference to the source model instance that can be used in custom
widget implementations, for example, to add data-* attributes to
<option> elements.
For example, consider the following models:
from django.db import models
class Topping(models.Model):
name = models.CharField(max_length=100)
price = models.DecimalField(decimal_places=2, max_digits=6)
def __str__(self):
return self.name
class Pizza(models.Model):
topping = models.ForeignKey(Topping, on_delete=models.CASCADE)
You can use a Select widget subclass to include
the value of Topping.price as the HTML attribute data-price for each
<option> element:
from django import forms
class ToppingSelect(forms.Select):
def create_option(self, name, value, label, selected, index, subindex=None, attrs=None):
option = super().create_option(name, value, label, selected, index, subindex, attrs)
if value:
option['attrs']['data-price'] = value.instance.price
return option
class PizzaForm(forms.ModelForm):
class Meta:
model = Pizza
fields = ['topping']
widgets = {'topping': ToppingSelect}
This will render the Pizza.topping select as:
<select id="id_topping" name="topping" required>
<option value="" selected>---------</option>
<option value="1" data-price="1.50">mushrooms</option>
<option value="2" data-price="1.25">onions</option>
<option value="3" data-price="1.75">peppers</option>
<option value="4" data-price="2.00">pineapple</option>
</select>
For more advanced usage you may subclass ModelChoiceIterator in order to
customize the yielded 2-tuple choices.
ModelChoiceIterator¶ModelChoiceIterator(field)¶The default class assigned to the iterator attribute of
ModelChoiceField and ModelMultipleChoiceField. An
iterable that yields 2-tuple choices from the queryset.
A single argument is required:
field¶The instance of ModelChoiceField or ModelMultipleChoiceField to
iterate and yield choices.
ModelChoiceIterator has the following method:
__iter__()¶Yields 2-tuple choices, in the (value, label) format used by
ChoiceField.choices. The first value element is a
ModelChoiceIteratorValue instance.
ModelChoiceIteratorValue¶ModelChoiceIteratorValue(value, instance)¶Two arguments are required:
value¶The value of the choice. This value is used to render the value
attribute of an HTML <option> element.
instance¶The model instance from the queryset. The instance can be accessed in
custom ChoiceWidget.create_option() implementations to adjust the
rendered HTML.
ModelChoiceIteratorValue has the following method:
__str__()¶Return value as a string to be rendered in HTML.
If the built-in Field classes don't meet your needs, you can create custom
Field classes. To do this, create a subclass of django.forms.Field. Its
only requirements are that it implement a 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
get_bound_field().
2022年6月01日