WTForms创建可变数量的字段

Question

我如何动态地创建几个带有不同问题的表单域，但答案相同？

from wtforms import Form, RadioField 
from wtforms.validators import Required 

class VariableForm(Form): 

    def __init__(formdata=None, obj=None, prefix='', **kwargs): 
     super(VariableForm, self).__init__(formdata, obj, prefix, **kwargs) 
     questions = kwargs['questions'] 
     // How to to dynamically create three questions formatted as below? 

    question = RadioField(
      # question ?, 
      [Required()], 
      choices = [('yes', 'Yes'), ('no', 'No')], 
      ) 

questions = ("Do you like peas?", "Do you like tea?", "Are you nice?") 
form = VariableForm(questions = questions) 

Answer 1

这是in the docs一直。

def my_view(): 
    class F(MyBaseForm): 
     pass 

    F.username = TextField('username') 
    for name in iterate_some_model_dynamically(): 
     setattr(F, name, TextField(name.title())) 

    form = F(request.POST, ...) 
    # do view stuff 

什么我不知道的是，类属性必须任何实例发生之前设置。清晰度来自于此bitbucket comment：

This is not a bug, it is by design. There are a lot of problems with adding fields to instantiated forms - For example, data comes in through the Form constructor.

If you reread the thread you link, you'll notice you need to derive the class, add fields to that, and then instantiate the new class. Typically you'll do this inside your view handler.

Answer 2

就快：

CHOICES = [('yes', 'Yes'), ('no', 'No')] 

class VariableForm(Form): 

    def __new__(cls, questions, **kwargs): 
     for index, question in enumerate(questions): 
      field_name = "question_{}".format(index) 
      field = RadioField(question, 
            validators=[Required()], 
            choices=CHOICES) 
      setattr(cls, field_name, field) 
     return super(VariableForm, cls).__new__(cls, **kwargs)