我在Appengine中将WTForms与Jinja2一起使用，并且有一个动态选项字段，其中城市的可用选择取决于地区的选择。现在，我还想对区域和城市启用验证（主要是在用户未选择区域/城市的情况下），但是我不知道该怎么做。您能告诉我如何修改表单类以启用动态选项验证吗？
我的形式课是
class InsertForm(Form):
categories = [
('1', _('All categories')),
('disabled', _('VEHICLES')),
('2010', _('Cars')),
('3', _('Motorcycles')),
('4', _('Accessories & Parts')),
('disabled', _('PROPERTIES')),
('7', _('Apartments')),
('8', _('Houses')),
('9', _('Commercial properties')),
('10', _('Land')),
('disabled', _('ELECTRONICS')),
('12', _('Mobile phones & Gadgets')),
('13', _('TV/Audio/Video/Cameras')),
('14', _('Computers')),
('disabled', _('HOME & PERSONAL ITEMS')),
('16', _('Home & Garden')),
('17', _('Clothes/Watches/Accessories')),
('18', _('For Children')),
('disabled', _('LEISURE/SPORTS/HOBBIES')),
('20', _('Sports & Outdoors')),
('21', _('Hobby & Collectables')),
('22', _('Music/Movies/Books')),
('23', _('Pets')),
('20', _('BUSINESS TO BUSINESS')),
('24', _('Hobby & Collectables')),
('25', _('Professional/Office equipment')),
('26', _('Business for sale')),
('disabled', _('JOBS & SERVICES')),
('28', _('Jobs')),
('29', _('Services')),
('30', _('Events & Catering')),
('31', _('Others')),
('1000', _('Sports & Outdoors')),
('1010', _('Hobby & Collectables')),
('1020', _('Hobby & Collectables')),
('1030', _('Music/Movies/Books')),
('1050', _('Pets')),
('1080', _('BUSINESS TO BUSINESS')),
('1100', _('Hobby & Collectables')),
('1090', _('Professional/Office equipment')),
('2010', _('Business for sale')),
('2030', _('Sports & Outdoors')),
('2040', _('Hobby & Collectables')),
('2080', _('Music/Movies/Books')),
('2070', _('Pets')),
('3000', _('BUSINESS TO BUSINESS')),
('3040', _('Hobby & Collectables')),
('3050', _('Professional/Office equipment')),
('3060', _('Business for sale')),
('4000', _('Sports & Outdoors')),
('4010', _('Hobby & Collectables')),
('4020', _('Music/Movies/Books')),
('4040', _('Pets')),
('4030', _('BUSINESS TO BUSINESS')),
('4090', _('Hobby & Collectables')),
('4060', _('Professional/Office equipment')),
('4070', _('Business for sale')),
('5030', _('Music/Movies/Books')),
('5020', _('Pets')),
('5010', _('BUSINESS TO BUSINESS')),
('5040', _('Hobby & Collectables')),
('6010', _('Professional/Office equipment')),
('6020', _('Business for sale')),
('6030', _('Music/Movies/Books')),
('6040', _('Pets')),
('7010', _('BUSINESS TO BUSINESS')),
('Other', _('Hobby & Collectables')),
]
regions = [('', _('Choose')), ('3', _('Delhi')), ('4', _('Maharasta'
)), ('7', _('Gujarat'))]
cities = [('', _('«Choose city»')), ('3', _('Mumbai')), ('4',
_('Delhi'))]
nouser = HiddenField(_('No user')) # dummy variable to know whether user is logged in
name = StringField(_('Name'),
[validators.Required(message=_('Name is required'
))], widget=MontaoTextInput())
title = StringField(_('Subject'),
[validators.Required(message=_('Subject is required'
))], widget=MontaoTextInput())
text = TextAreaField(_('Ad text'),
[validators.Required(message=_('Text is required'
))], widget=MontaoTextArea())
phonenumber = TextField(_('Phone'), [validators.Optional()])
type = StringField(_('Type'),
[validators.Required(message=_('Type is required'
))])
phoneview = BooleanField(_('Display phone number on site'))
price = StringField(_('Price'), [validators.Regexp('^[0-9]+$',
message=_(
'This is not an integer number, please see the example and try again'
)), validators.Optional()], widget=MontaoTextInput())
email = StringField(_('Email'),
[validators.Required(message=_('Email is required'
)),
validators.Email(message=_('Your email is invalid'
))], widget=MontaoTextInput())
#area = SelectField(_('City'), choices=cities,
# validators=[validators.Optional()])
category_group = SelectField(_('Category'), choices=categories,
validators=[validators.Required(message=_('Category is required'
))])
def validate_name(form, field):
if len(field.data) > 50:
raise ValidationError(_('Name must be less than 50 characters'
))
def validate_email(form, field):
if len(field.data) > 60:
raise ValidationError(_('Email must be less than 60 characters'
))
def validate_price(form, field):
if len(field.data) > 8:
raise ValidationError(_('Price must be less than 9 integers'
))
def validate_area(form, field):
if len(field.data) > 888:
raise ValidationError(_('Dummy validator'
))
在我的HTML中，我有一个脚本，可启用某个区域的城市。
<select onchange="cities(this);document.getElementById('area').display='';" name="region" id="region">
<option value="">«{% trans %}Choose region{% endtrans %}»</option>
...
最佳答案
我做类似的事情，每种可能性都有不同的WTForm －在您的情况下，我猜想每种地区都有。
在服务器上，当您收到表单数据时，首先要使用表单数据中的区域来选择处理所有表单数据所需的表单。
就您而言，您可以拥有一个基本表格，其中包含除城市以外的所有信息。永远不会使用此表格，但是您可以为每个区域创建该表格的子类，并在其中为该区域指定适当的城市。像这样：
class DelhiInsertForm(InsertForm):
cities = SelectField(...)
class MaharastaInsertForm(InsertForm):
cities = SelectField(...)
在客户端，我将使用jQuery / Javascript更新在用户选择区域后呈现给用户的城市表单字段。