每天40分玩转Django：Django表单集

Django表单集

一、知识要点概览表

类别	知识点	掌握程度要求
基础概念	FormSet、ModelFormSet	深入理解
内联表单集	InlineFormSet、BaseInlineFormSet	熟练应用
表单集验证	clean方法、验证规则	熟练应用
自定义配置	extra、max_num、can_delete	理解应用
动态管理	JavaScript动态添加/删除表单	掌握使用

二、基础模型和表单设置

# models.py
from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=100)
    email = models.EmailField()
    bio = models.TextField()

    def __str__(self):
        return self.name

class Book(models.Model):
    author = models.ForeignKey(Author, on_delete=models.CASCADE)
    title = models.CharField(max_length=200)
    isbn = models.CharField(max_length=13)
    publication_date = models.DateField()
    price = models.DecimalField(max_digits=10, decimal_places=2)

    def __str__(self):
        return self.title

# forms.py
from django import forms
from .models import Author, Book

class AuthorForm(forms.ModelForm):
    class Meta:
        model = Author
        fields = ['name', 'email', 'bio']

class BookForm(forms.ModelForm):
    class Meta:
        model = Book
        fields = ['title', 'isbn', 'publication_date', 'price']

三、基本表单集实现

1. 创建表单集

# forms.py
from django.forms import modelformset_factory, formset_factory

# 创建Book模型的表单集
BookFormSet = modelformset_factory(
    Book,
    form=BookForm,
    extra=2,  # 额外空表单数量
    max_num=5,  # 最大表单数量
    can_delete=True  # 允许删除
)

# 创建自定义表单集
class BaseBookFormSet(forms.BaseModelFormSet):
    def clean(self):
        super().clean()
        titles = []
        for form in self.forms:
            if form.cleaned_data:
                title = form.cleaned_data.get('title')
                if title in titles:
                    raise forms.ValidationError("书籍标题不能重复")
                titles.append(title)

# 使用自定义表单集基类
BookFormSet = modelformset_factory(
    Book,
    form=BookForm,
    formset=BaseBookFormSet,
    extra=2
)

2. 视图实现

# views.py
from django.shortcuts import render, redirect
from django.contrib import messages
from .forms import BookFormSet, AuthorForm

class BookFormSetView(View):
    template_name = 'books/book_formset.html'
    
    def get(self, request):
        formset = BookFormSet(queryset=Book.objects.none())
        return render(request, self.template_name, {'formset': formset})
    
    def post(self, request):
        formset = BookFormSet(request.POST)
        if formset.is_valid():
            instances = formset.save()
            messages.success(request, f'成功保存{len(instances)}本书籍信息')
            return redirect('book_list')
        return render(request, self.template_name, {'formset': formset})

def manage_books(request, author_id):
    author = get_object_or_404(Author, id=author_id)
    
    if request.method == 'POST':
        formset = BookFormSet(
            request.POST,
            queryset=Book.objects.filter(author=author)
        )
        if formset.is_valid():
            books = formset.save(commit=False)
            for book in books:
                book.author = author
                book.save()
            # 处理删除的书籍
            for obj in formset.deleted_objects:
                obj.delete()
            return redirect('author_detail', pk=author.pk)
    else:
        formset = BookFormSet(queryset=Book.objects.filter(author=author))
    
    return render(request, 'books/manage_books.html', {
        'formset': formset,
        'author': author
    })

四、内联表单集实现

1. 创建内联表单集

# forms.py
from django.forms import inlineformset_factory

# 创建Author-Book内联表单集
BookInlineFormSet = inlineformset_factory(
    Author,  # 父模型
    Book,    # 子模型
    form=BookForm,
    extra=2,
    max_num=5,
    can_delete=True
)

# 自定义内联表单集
class BaseBookInlineFormSet(forms.BaseInlineFormSet):
    def clean(self):
        super().clean()
        total_price = 0
        for form in self.forms:
            if form.cleaned_data and not form.cleaned_data.get('DELETE', False):
                price = form.cleaned_data.get('price', 0)
                total_price += price
                
        if total_price > 1000:
            raise forms.ValidationError(
                "所有书籍总价不能超过1000"
            )

# 使用自定义内联表单集
BookInlineFormSet = inlineformset_factory(
    Author,
    Book,
    form=BookForm,
    formset=BaseBookInlineFormSet,
    extra=2
)

2. 视图实现

# views.py
from django.views.generic.edit import UpdateView
from .forms import BookInlineFormSet

class AuthorBooksUpdateView(UpdateView):
    model = Author
    form_class = AuthorForm
    template_name = 'books/author_books_form.html'
    
    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        if self.request.POST:
            context['book_formset'] = BookInlineFormSet(
                self.request.POST,
                instance=self.object
            )
        else:
            context['book_formset'] = BookInlineFormSet(
                instance=self.object
            )
        return context
    
    def form_valid(self, form):
        context = self.get_context_data()
        book_formset = context['book_formset']
        if book_formset.is_valid():
            self.object = form.save()
            book_formset.instance = self.object
            book_formset.save()
            return redirect('author_detail', pk=self.object.pk)
        return self.render_to_response(self.get_context_data(form=form))

五、表单集模板实现

<!-- templates/books/author_books_form.html -->
{% extends 'base.html' %}
{% load static %}

{% block content %}
<div class="container">
    <h1>编辑作者及其书籍</h1>
    
    <form method="post">
        {% csrf_token %}
        
        <div class="author-form">
            <h2>作者信息</h2>
            {{ form.as_p }}
        </div>
        
        <div class="books-formset">
            <h2>书籍信息</h2>
            {{ book_formset.management_form }}
            
            <div id="book-forms">
                {% for book_form in book_formset %}
                <div class="book-form">
                    {{ book_form.non_field_errors }}
                    <div class="form-row">
                        <div class="form-group">
                            {{ book_form.title.label_tag }}
                            {{ book_form.title }}
                            {{ book_form.title.errors }}
                        </div>
                        <div class="form-group">
                            {{ book_form.isbn.label_tag }}
                            {{ book_form.isbn }}
                            {{ book_form.isbn.errors }}
                        </div>
                        <div class="form-group">
                            {{ book_form.price.label_tag }}
                            {{ book_form.price }}
                            {{ book_form.price.errors }}
                        </div>
                        {% if book_form.instance.pk %}
                            {{ book_form.DELETE }}
                        {% endif %}
                    </div>
                </div>
                {% endfor %}
            </div>
            
            <button type="button" id="add-book" class="btn btn-secondary">
                添加书籍
            </button>
        </div>
        
        <button type="submit" class="btn btn-primary mt-3">
            保存
        </button>
    </form>
</div>

{% block extra_js %}
<script>
$(document).ready(function() {
    // 获取表单总数
    const totalForms = $('#id_book_set-TOTAL_FORMS');
    
    // 添加新书籍表单
    $('#add-book').click(function() {
        const formCount = parseInt(totalForms.val());
        const newForm = $('#book-forms .book-form:first').clone(true);
        
        // 更新表单索引
        newForm.find(':input').each(function() {
            const name = $(this).attr('name').replace('-0-', '-' + formCount + '-');
            const id = 'id_' + name;
            $(this).attr({'name': name, 'id': id}).val('');
        });
        
        // 更新标签的for属性
        newForm.find('label').each(function() {
            const newFor = $(this).attr('for').replace('-0-', '-' + formCount + '-');
            $(this).attr('for', newFor);
        });
        
        // 添加新表单到DOM
        $('#book-forms').append(newForm);
        totalForms.val(formCount + 1);
    });
});
</script>
{% endblock %}
{% endblock %}

六、表单集处理流程图

在这里插入图片描述

七、高级用法示例

1. 工厂函数自定义

def get_book_formset(extra=1, max_num=None):
    return modelformset_factory(
        Book,
        form=BookForm,
        extra=extra,
        max_num=max_num,
        validate_max=True,
        can_delete=True,
        widgets={
            'title': forms.TextInput(attrs={'class': 'form-control'}),
            'isbn': forms.TextInput(attrs={'class': 'form-control'}),
            'price': forms.NumberInput(attrs={'class': 'form-control'})
        }
    )

# 在视图中使用
def manage_books_dynamic(request):
    BookFormSet = get_book_formset(
        extra=2,
        max_num=10
    )
    if request.method == 'POST':
        formset = BookFormSet(request.POST)
        if formset.is_valid():
            formset.save()
            return redirect('book_list')
    else:
        formset = BookFormSet()
    return render(request, 'books/manage_books.html', {'formset': formset})

2. 条件验证

class BaseBookFormSet(forms.BaseModelFormSet):
    def clean(self):
        super().clean()
        
        # 检查ISBN唯一性
        isbns = []
        for form in self.forms:
            if form.cleaned_data and not form.cleaned_data.get('DELETE', False):
                isbn = form.cleaned_data.get('isbn')
                if isbn in isbns:
                    raise forms.ValidationError('ISBN必须唯一')
                isbns.append(isbn)
        
        # 检查总价格
        total_price = sum(
            form.cleaned_data.get('price', 0)
            for form in self.forms
            if form.cleaned_data and not form.cleaned_data.get('DELETE', False)
        )
        if total_price > 1000:
            raise forms.ValidationError('所有书籍总价不能超过1000')

3. 动态表单处理

# views.py
from django.http import JsonResponse

class DynamicBookFormView(View):
    def post(self, request):
        if request.is_ajax():
            formset = BookFormSet(request.POST)
            if formset.is_valid():
                instances = formset.save()
                return JsonResponse({
                    'status': 'success',
                    'message': f'成功保存{len(instances)}本书籍'
                })
            else:
                errors = []
                for form in formset:
                    for field, error in form.errors.items():
                        errors.append(f"{field}: {error}")
                return JsonResponse({
                    'status': 'error',
                    'errors': errors
                })
        return JsonResponse({'status': 'error', 'message': '非法请求'})