基于ChoiceField+Form组件实现网页下拉数据实时更新

1.urls.py --> 设置一个访问路径

# 导入三个模块文件
from django.contrib import admin
from django.urls import re_path
from app01 import views

# 设置URL路径
urlpatterns = [
    re_path('admin/', admin.site.urls),
    re_path('test/', views.test, name='test'),
]

2.test.html --> 创建一个html页面

<!-- 用之前先引入bootstrap的cdn资源 -->
<div class="container">
    <div class="row">
    <form action="{% url 'test' %}" method="POST" novalidate="novalidate">
        {% csrf_token %}
        {% for field in obj %}
            <hr>
            {{ field.label_tag }}
            <hr>
            {{ field }}
            {{ field.errors.0 }}
        {% endfor %}
        <hr>
        <input type="submit" value="提交">
    </form>
    </div>
</div>

3.models.py --> 设置models模型类

from django.db import models

class UserType(models.Model):
    caption = models.CharField(max_length=32)

class UserInfo(models.Model):
    username = models.CharField(max_length=32)
    email = models.EmailField()
    user_type = models.ForeignKey(to='UserType', to_field='id', on_delete=models.CASCADE)

4.forms.py --> 设置form组件验证

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from django import forms
from django.forms import widgets
from django.forms import fields
from app01.models import UserType
class UserInfoForm(forms.Form):
    # username = models.CharField(max_length=32)    <--> models
    username = fields.CharField(max_length=32)
    # email = models.EmailField()    <-- models
    email = fields.EmailField()
    # user_type = models.ForeignKey(to='UserType',to_field='id')    <--> models

　　# user_type字段用__init__实时更新,与数据库保持同步
    user_type = fields.ChoiceField(
    )
    # 下面的操作是让数据在网页上实时更新
    def __init__(self, *args, **kwargs):
        super(UserInfoForm, self).__init__(*args, **kwargs)
        self.fields['user_type'].choices = UserType.objects.values_list('id', 'caption')

5.views.py --> 设置views视图函数

from django.shortcuts import render, HttpResponse, redirect
from app01.forms import UserInfoForm
def test(request):
    if request.method == 'GET':
        obj = UserInfoForm()
        return render(request, 'test.html', {'obj':obj})
    else:
        obj = UserInfoForm(request.POST)
        return render(request, 'test.html', {'obj':obj})