Django -手动表单字段渲染添加类

from django import forms

class ContactForm(forms.Form):
    name = forms.CharField(max_length=100)
    email = forms.EmailField()
    message = forms.CharField(widget=forms.Textarea)

<form method="post">
    {% csrf_token %}
    <div class="form-group">
        <label for="{{ form.name.id_for_label }}">Name:</label>
        {{ form.name|add_class:"form-control" }}
    </div>
    <div class="form-group">
        <label for="{{ form.email.id_for_label }}">Email:</label>
        {{ form.email|add_class:"form-control" }}
    </div>
    <div class="form-group">
        <label for="{{ form.message.id_for_label }}">Message:</label>
        {{ form.message|add_class:"form-control" }}
    </div>
    <button type="submit" class="btn btn-primary">Submit</button>
</form>

# myapp/templatetags/custom_filters.py
from django import template

register = template.Library()

@register.filter(name='add_class')
def add_class(value, arg):
    return value.as_widget(attrs={'class': arg})

{% load custom_filters %}