Django如何在表单保存中关联外键对象

from django.db import models

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

class MainModel(models.Model):
    foreign_key = models.ForeignKey(ForeignKeyModel, on_delete=models.CASCADE)
    # 其他字段...

from django import forms
from .models import MainModel

class MainModelForm(forms.ModelForm):
    class Meta:
        model = MainModel
        fields = ['foreign_key', 'other_field1', 'other_field2']

from django.shortcuts import render, redirect
from .forms import MainModelForm

def save_form(request):
    if request.method == 'POST':
        form = MainModelForm(request.POST)
        if form.is_valid():
            main_model = form.save()  # 保存表单数据到数据库
            return redirect('success')  # 重定向到成功页面
    else:
        form = MainModelForm()
    
    return render(request, 'form.html', {'form': form})