一、创建ModelForm
from django.forms import ModelForm from appxx import models from django.forms import widgets as wdt # 因为重名，所以起个别名 #定义一个类，比如BookForm，这个类要继承ModelForm，在这个类中再写一个原类Meta（规定写法，注意首字母是大写的） #在这个原类中，有以下属性（部分）： class BookForm(ModelForm): class Meta: model = models.Book # 对应的Model中的类 fields = "__all__" # 字段，如果是__all__，就表示列出所有的字段，或者使用列表列出想要的字段 exclude = None # 排除的字段 # error_messages用法 error_messages = { "title": {"required": "书名不能为空"}, "price": {"required": "售价不能为空"}, } # widgets用法，比如把输入用户名的input框给为Textarea widgets = { "name": wdt.Textarea(attrs={"class": "c1"}) # 还可以自定义属性 } #labels，自定义在前端显示的名字 labels= { "title": "书名", "price": "售价", }
然后在 url 对应的视图函数中实例化这个类，把这个对象传给前端：
def add_book(request): form = forms.BookForm() return render(request, "add_book.html", {"form": form})
然后在前端像Form组件那样渲染页面，具体点击这里
二、添加数据
保存数据的时候，不用挨个取数据了，只需要 save 一下即可。
from django.shortcuts import render,redirect from appxx import models from appxx import forms def add_book(request): if request.method == "POST": form = forms.BookForm(request.POST) if form.is_valid(): form.save() return redirect("/book/") form = forms.BookForm() return render(request, "add_book.html", {"form": form})
三、编辑数据
如果不使用 ModelForm，编辑的时候得显示之前的数据，还得挨个取一遍值；如果使用 ModelForm，只需要加一个instance=obj（obj是要修改的数据库的一条数据的对象）就可以得到同样的效果。
保存的时候要注意，一定要注意有这个对象（instance=obj），否则不知道更新哪一个数据。
from django.shortcuts import render,redirect from appxx import models from appxx import forms def edit_book(request, edit_book_id): edit_book= models.Book.objects.filter(id=edit_book_id).first() if request.method == "POST": form = forms.BookForm(request.POST, instance=edit_book) if form.is_valid(): form.save() return redirect("/book/") form = forms.BookForm(instance=edit_book) return render(request, "edit_book.html", {"form": form})
总结： 从上边可以看到 ModelForm 用起来是非常方便的，比如增加修改之类的操作。但是也带来额外不好的地方，model和form之间耦合了。如果不耦合的话，form.save()方法也无法直接提交保存。 但是耦合的话使用场景通常局限用于小程序，写大程序就最好不用了。
四、完整示例代码
项目结构
urls.py
from django.conf.urls import url from django.contrib import admin from appxx import views urlpatterns = [ url(r'^admin/', admin.site.urls), url(r"^book/$", views.book), url(r"^book/add/", views.add_book), url(r"^book/edit/(d+)/", views.edit_book), ]
views.py
from django.shortcuts import render,redirect from appxx import models from appxx import forms def book(request): book_list = models.Book.objects.all() return render(request, "book.html", {"book_list": book_list}) def add_book(request): if request.method == "POST": form = forms.BookForm(request.POST) if form.is_valid(): form.save() return redirect("/book/") form = forms.BookForm() return render(request, "add_book.html", {"form": form}) def edit_book(request, edit_book_id): edit_book= models.Book.objects.filter(id=edit_book_id).first() if request.method == "POST": form = forms.BookForm(request.POST, instance=edit_book) if form.is_valid(): form.save() return redirect("/book/") form = forms.BookForm(instance=edit_book) return render(request, "edit_book.html", {"form": form})
models.py
from django.db import models class Book(models.Model): id = models.AutoField(primary_key=True) title = models.CharField(max_length=32) price = models.DecimalField(max_digits=5, decimal_places=2) publish_date = models.DateField() publisher = models.ForeignKey(to="Publisher") authors = models.ManyToManyField(to="Author") def __str__(self): return self.title class Publisher(models.Model): id = models.AutoField(primary_key=True) name = models.CharField(max_length=32) def __str__(self): return self.name class Author(models.Model): id = models.AutoField(primary_key=True) name = models.CharField(max_length=32) def __str__(self): return self.name
forms.py
from django.forms import ModelForm from appxx import models from django.forms import widgets as wdt class BookForm(ModelForm): class Meta: model = models.Book fields = "__all__" labels = { "title": "书名", "price": "售价", "publish_date": "出版日期", "publisher": "出版社", "authors": "作者" } widgets = { "title": wdt.TextInput(attrs={"class": "form-control"}), "price": wdt.TextInput(attrs={"class": "form-control"}), "publish_date": wdt.TextInput(attrs={"class": "form-control", "type": "date"}), "publisher": wdt.Select(attrs={"class": "form-control"}), "authors": wdt.SelectMultiple(attrs={"class": "form-control"}), } error_messages = { "title": {"required": "书名不能为空"}, "price": {"required": "售价不能为空"}, "publish_date": {"required": "出版日期不能为空"}, "publisher": {"required": "出版社不能为空"}, "authors": {"required": "作者不能为空"}, }
book.html
<!DOCTYPE html> <html lang="zh-cn"> <head> <meta charset="UTF-8"> <title>展示书籍</title> <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css"> </head> <body> <div class="container"> <div class="row"> <div class="col-md-6 col-md-offset-3"> <span><a class="btn btn-primary" href="/book/add/">添加</a></span> <table class="table table-striped table-bordered"> <thead> <tr> <th>序号</th> <th>书名</th> <th>售价</th> <th>出版日期</th> <th>出版社</th> <th>作者</th> <th>操作</th> </tr> </thead> <tbody> {% for book in book_list %} <tr> <td>{{ forloop.counter }}</td> <td>{{ book.title }}</td> <td>{{ book.price }}</td> <td>{{ book.publish_date }}</td> <td>{{ book.publisher.name }}</td> <td> {% for author in book.authors.all %} {{ author.name }} {% endfor %} </td> <td> <span><a class="btn btn-warning" href="/book/edit/{{ book.pk }}/">编辑</a></span> <span><a class="btn btn-danger" href="">删除</a></span> </td> </tr> {% endfor %} </tbody> </table> </div> </div> </div> </body> </html>
add_book.html和edit_book.html（两个页面代码一样）
<!DOCTYPE html> <html lang="zh-cn"> <head> <meta charset="UTF-8"> <title>添加书籍</title> <link rel="stylesheet" href="/static/bootstrap/css/bootstrap.min.css"> <style> .panel-title { font-weight: bolder; } .panel { margin-top: 30px; } </style> </head> <body> <div class="container"> <div class="row"> {# panel开始 #} <div class="panel panel-danger col-sm-6 col-md-6 col-sm-offset-3 col-md-offset-3"> <div class="panel-heading"> <h3 class="panel-title">添加书籍</h3> </div> {# panel-body开始 #} <div class="panel-body"> {# form开始 #} <form class="form-horizontal" action="" method="post" novalidate> {% csrf_token %} <div class="form-group"> <label class="col-md-2 control-label" for="{{ form.title.id_for_label }}">{{ form.title.label }}</label> <div class="col-md-10"> {{ form.title }} </div> </div> <div class="form-group"> <label class="col-md-2 control-label" for="{{ form.price.id_for_label }}">{{ form.price.label }}</label> <div class="col-md-10"> {{ form.price }} </div> </div> <div class="form-group"> <label class="col-md-2 control-label" for="{{ form.publish_date.id_for_label }}">{{ form.publish_date.label }}</label> <div class="col-md-10"> {{ form.publish_date }} </div> </div> <div class="form-group"> <label class="col-md-2 control-label" for="{{ form.publisher.id_for_label }}">{{ form.publisher.label }}</label> <div class="col-md-10"> {{ form.publisher }} </div> </div> <div class="form-group"> <label class="col-md-2 control-label" for="{{ form.authors.id_for_label }}">{{ form.authors.label }}</label> <div class="col-md-10"> {{ form.authors }} </div> </div> <div class="form-group"> <div class="col-md-offset-2 col-md-10"> <button type="submit" class="btn btn-success">提交</button> <a class="btn btn-warning pull-right" href="/book/">取消</a> </div> </div> </form> {# form结束 #} </div> {# panel-body结束 #} </div> {# panel结束 #} </div> </div> </body> </html>