来自URL参数的默认ModelForm字段(外键)

# models.py
from django.db import models

class Category(models.Model):
    name = models.CharField(max_length=50)

class Product(models.Model):
    name = models.CharField(max_length=50)
    category = models.ForeignKey(Category, on_delete=models.CASCADE)

# forms.py
from django import forms
from .models import Product

class ProductForm(forms.ModelForm):
    class Meta:
        model = Product
        fields = '__all__'

# views.py
from django.shortcuts import render
from .forms import ProductForm

def create_product(request, category_id):
    # 使用URL参数中的category_id设置默认值
    form = ProductForm(initial={'category': category_id})
    
    if request.method == 'POST':
        form = ProductForm(request.POST)
        if form.is_valid():
            form.save()
            return redirect('product_list')
    
    return render(request, 'create_product.html', {'form': form})

# create_product.html
<form method="POST">
  {% csrf_token %}
  {{ form.as_p }}
  <input type="submit" value="Create">
</form>