Django ModelForm组件使用方法详解
框架(架构)  /  管理员 发布于 5年前   152
一、创建ModelForm
from django.forms import ModelFormfrom appxx import modelsfrom 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
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,redirectfrom appxx import modelsfrom appxx import formsdef 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,redirectfrom appxx import modelsfrom appxx import formsdef 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 urlfrom django.contrib import adminfrom appxx import viewsurlpatterns = [ 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,redirectfrom appxx import modelsfrom appxx import formsdef 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 modelsclass 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.titleclass Publisher(models.Model): id = models.AutoField(primary_key=True) name = models.CharField(max_length=32) def __str__(self): return self.nameclass 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 ModelFormfrom appxx import modelsfrom django.forms import widgets as wdtclass 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="https:static/bootstrap/css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" ></head><body><div class="container"> <div class="row"> <div class="col-md-6 col-md-offset-3"> <span><a class="btn btn-primary" href="https:book/add/" rel="external nofollow" >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="https:book/edit/{{ book.pk }}/" rel="external nofollow" >编辑</a></span> <span><a class="btn btn-danger" href="https:/article/">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="https:static/bootstrap/css/bootstrap.min.css" rel="external nofollow" rel="external nofollow" > <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="https:book/" rel="external nofollow" >取消</a></div> </div> </form> {# form结束 #} </div> {# panel-body结束 #} </div> {# panel结束 #} </div></div></body></html>
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。
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