如何从使用WTForm构建的表单中清空数值

Question

我有这个小的Flask程序。它期望用户的姓名和年龄，然后打印一条消息。真的很容易，因为我刚刚开始使用Python和Flask。

from flask import Flask, render_template
from flask.ext.bootstrap import Bootstrap 
from flask.ext.wtf import Form 
from wtforms import StringField, IntegerField, SubmitField
from wtforms.validators import Required, Length, NumberRange

app = Flask(__name__)
app.config['SECRET_KEY'] = 'top secret!'
bootstrap = Bootstrap(app)

class NameForm(Form):
    name = StringField('What is your name?', validators = [Required(), Length(1, 16)])
    age  = IntegerField('How old are you?', validators = [Required(), NumberRange(min=1, max=99, message="Should be between 1 and 99")])

    submit = SubmitField('Submit')

@app.route('/', methods=['GET', 'POST'])
def index():
    name = None
    age  = None
    form = NameForm()
    if form.validate_on_submit():
        name = form.name.data
        age  = form.age.data
        form.age.raw_data = None
        form.name.data = ''

    return render_template('index.html', form = form, name = name, age = age)

if __name__ == '__main__':
    app.run(debug = True)

而且，对于HTML模板，我有：{％扩展了“ bootstrap / base.html”％}

{% block title %}Form Example{% endblock %}

{% block navbar %}
    <nav class="navbar navbar-inverse" role="navigation">
        <div class="container">
            <a href="{{ url_for('index') }}" class="navbar-brand">Hello</a>
        </div>
    </nav>
{% endblock %}

{% block content %}
    <div class="container">
        <form method="POST" action="">
            {{ form.name.label }} {{ form.name(size=16, class='name-field') }}
            {% for error in form.name.errors %}
                {{ error }}
            {% endfor %}

            <br>

            {{ form.age.label }} {{ form.age(class='age-field') }}
            {% for error in form.age.errors %}
                {{ error }}
            {% endfor %}

            <br />
            {{ form.submit() }}
            {{ form.hidden_tag() }}
        </form>
        {% if name %}
            <h1>Hello, {{ name.capitalize() }}</h1>
            <h2>You're {{ age }} years old.</h2>
        {% endif %}
    </div>
{% endblock %}

我的问题是，提交表单后，名称输入为空，但年龄输入为空。为什么？如何清空数字字段？

谢谢。

Answer 1

感谢您提出一个明确的问题-我想到的最简单的空白表单创建方法是创建表单，并告诉它忽略请求表单数据。

@app.route('/', methods=['GET', 'POST'])
def index():
    form = NameForm()  # Auto-populates from request data.
    name = None
    age = None
    if form.validate_on_submit():
        name = form.name.data
        age  = form.age.data

        # Lets now create a form, but ignore the request data, so it's empty:
        form = NameForm(formdata=None)
    return render_template('index.html', form = form, name = name, age = age)

另外，我注意到您正在使用Required()它，并且正在被DataRequired()WTF v3 取代，因此您可能要立即开始使用它，您将来的自己会感谢您！