基于下拉值选择显示Django ModelForm中的链接

Question

我使用基于类的通用视图和forms.ModelForm作为form_class属性。如何根据表单的下拉值在ModelForm中显示链接？

我将这个最小的，可重现的例子上传到了GitHub HERE。

git clone https://github.com/jaradc/SO939393.git

我想要实现的目标：当选择下拉列表中的项目时，在选择后立即显示下拉列表下方文件的链接。

视觉：

表格上载了请求
用户从“模型一”下拉列表中选择一个项目
一些内部流程：获取ModelOne sample_input_file位置将该位置作为链接注入“模型一”字段下面的表单

QUICK VIEW（这是整个项目）

如果这太压倒了，你可以忽略它！我提供完整的上下文，以防有人想要查看每个细节。

项目名称：SO939393

应用名称：myapp

SO939393 / urls.py

from django.contrib import admin
from django.urls import path, include

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('myapp.urls'))
]

SO939393 / settings.py

INSTALLED_APPS = [
    'django.contrib.admin',
    ...
    'myapp.apps.MyappConfig',
]

的myapp / models.py

from django.db import models

class ModelOne(models.Model):
    name = models.CharField(max_length=100)
    large_pickle_file = models.FileField()
    sample_input_file = models.FileField()

    def __str__(self):
        return self.name

class ModelTwo(models.Model):
    name = models.CharField(max_length=100)
    model_one = models.ForeignKey(ModelOne, on_delete=models.CASCADE)
    upload_file = models.FileField()

    def __str__(self):
        return self.name

MYAPP / urls.py

from django.urls import path
from . import views

urlpatterns = [
    path('', views.HomeView.as_view(), name='home'),
    path('create/', views.Create.as_view(), name='create')
]

MYAPP / forms.py

from django import forms
from .models import ModelTwo

class ModelTwoForm(forms.ModelForm):
    class Meta:
        model = ModelTwo
        fields = ['name', 'model_one', 'upload_file']

MYAPP / views.py

from django.shortcuts import render
from django.views.generic.edit import CreateView, UpdateView, DeleteView
from django.views.generic.list import ListView
from .forms import ModelTwoForm
from .models import ModelTwo

class HomeView(ListView):
    model = ModelTwo
    template_name = 'myapp/base.html'

class Create(CreateView):
    form_class = ModelTwoForm
    model = ModelTwo
    template_name = 'myapp/create_form.html'
    success_url = '/'

MYAPP /模板/ MYAPP / base.html文件

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
{% block content %}
    <h1><a href="{% url 'create' %}">Create</a> an Item</h1>
    <ul>
        {% for item in object_list %}
            <li>{{ item.name }} - {{ item.model_one.name }}</li>
        {% empty %}
            <li>No items yet.</li>
        {% endfor %}
    </ul>
{% endblock %}
{% block custom_js %}{% endblock %}
</body>
</html>

MYAPP /模板/ MYAPP / create_form.html

{% load static %}
{% block content %}
    <div class="container col-5">
        <form action="" method="POST" enctype="multipart/form-data">
            {% csrf_token %}
            {{ form.as_p }}
            <input type="submit" value="Save" />
        </form>
    </div>
{% endblock %}

{% block custom_js %}<script>{% static 'myapp/custom.js' %}</script>{% endblock %}

MYAPP / admin.py

from django.contrib import admin
from .models import ModelOne, ModelTwo

admin.site.register(ModelOne)
admin.site.register(ModelTwo)

MYAPP /静态/ MYAPP / custom.js

# this file is empty but mentioning just in-case javascript is the way to go here