使字段有条件地成为必填项 Field Flask Forms

Question

我有两个烧瓶形式的单选按钮。如果使用 "Yes" 选中第一个单选按钮，我需要第二个单选按钮成为用户必须填写的内容。我知道在 javascript 中有一些方法可以做到这一点，但我想将所有内容都包含在 flask wtform 中，因为这是我最常做的事情，而且我是 javascript 的新手。

在查看了以前的 Whosebug 问题后，我找到了以下可能的解决方案，但这对我没有任何帮助。当我运行具有以下解决方案的代码时，两个单选按钮都是必需的。如果仅使用 "Yes" 检查第一个，我希望第二个是强制性的。

class RequiredIf(InputRequired):
    field_flags = ('requiredif',)

    def __init__(self, other_field_name, message=None, *args, **kwargs):
        self.other_field_name = other_field_name
        self.message = message

    def __call__(self, form, field):
        other_field = form[self.other_field_name]
        if other_field is None:
            raise Exception('no field named "%s" in form' % self.other_field_name)
        if bool(other_field.data):
            super(RequiredIf, self).__call__(form, field)
        else:
            Optional().__call__(form, field)


class CheckInForm(FlaskForm):
    question1= RadioField('Question1 Label', choices=[('Yes', 'Yes'), ('No', 'No')], validators=[DataRequired()])

    question2 = RadioField('Question2 Label', choices=[('Yes', 'Yes'), ('No', 'No')], validators=[RequiredIf('question1')])
    submit = SubmitField('Submit Form', render_kw={"class": "btn btn-primary btn-block"})

以下是我的html文件：

{% extends "base.html" %}
{% import 'wtf.html' as wtf %}

<body>
{% block app_content %}
{% block content %}
    <h1><center>Check In</center></h1>
    <form action="" method="post" novalidate>
        {{ form.hidden_tag() }}


        <h5>&emsp;{{ form.question1.label }}</h5>
        {% for subfield in form.question1%}
            <tr>&emsp;
                <td>{{ subfield }}</td>
                <td>{{ subfield.label }}</td> &emsp;
            </tr>
        {% endfor %}
        {% for error in form.question1.errors %}
            <span style="color: red;">[{{ error }}]</span>
        {% endfor %}



        <h5>&emsp;{{ form.question2.label }}</h5>
        {% for subfield in form.question2%}
            <tr>&emsp;
                <td>{{ subfield }}</td>
                <td>{{ subfield.label }}</td> &emsp;
            </tr>
        {% endfor %}
        {% for error in form.question2.errors %}
            <span style="color: red;">[{{ error }}]</span>
        {% endfor %}

    </form>
{% endblock %}
{% endblock %}

Answer 1

这一行有问题：

if bool(other_field.data):

当为 question1 做出选择时，other_field.data 是字符串值 'Yes' 或 'No'，并且 bool(other_field.data) 始终是 True .

Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 23:11:46) [MSC v.1916 64 bit (AMD64)] on win32
>>> print(bool('No'))
True
>>> print(bool('Yes'))
True

您需要显式测试字符串值 'No'。例如

class RequiredIf(InputRequired):
    field_flags = ('requiredif',)

    def __init__(self, other_field_name, message=None, *args, **kwargs):
        self.other_field_name = other_field_name
        self.message = message

    def __call__(self, form, field):
        other_field = form[self.other_field_name]
        if other_field is None:
            raise Exception('no field named "%s" in form' % self.other_field_name)
        if other_field.data == 'No':
            Optional().__call__(form, field)
        else:
            super(RequiredIf, self).__call__(form, field)

使字段有条件地成为必填项 Field Flask Forms

Make field Required conditionally Field Flask Forms

python

flask

flask-wtforms

使字段有条件地成为必填项 F​​ield Flask Forms

Make field Required conditionally Field Flask Forms

python

flask

flask-wtforms

使字段有条件地成为必填项 Field Flask Forms