一 定义模型类

• 定义三个数据，分别是做user，goods，count的外键

  model. py
  class CartInfo(models.Model):
    user=models.ForeignKey('df_user.UserInfo')
    goods=models.ForeignKey('df_goods.GoodsInfo')
    count=models.IntegerField(default=0)
  

• 定义views页面函数，使其可以传送数据

   views.py
   @islogin
   def cart(request):
       uid = request.session['user_id']
       carts = CartInfo.objects.filter(user_id=uid)
       lenn = len(carts)
       context={'title':'购物车',
                'page_name':1,
                'carts':carts,
                'len':lenn}
       return render(request,'df_cart/cart.html',context)
  
   #添加商品
   @islogin
   def add(request,gid,count):
       #用户uid购买了gid商品，数量为count
       uid=request.session['user_id']
       gid = int(gid)
       count = int(count)
       #查询购物车是否已经有此商品，有则增加
       carts = CartInfo.objects.filter(user_id=uid, goods_id=gid)
       if len(carts)>=1:
           cart=carts[0]
           # print '*'*10
           # print cart  -> 购物车商品数量
           cart.count=cart.count+count
       else:#不存在则直接加
           cart=CartInfo()
           cart.user_id=uid
           cart.goods_id=gid
           cart.count=count
       cart.save()
       count_s = CartInfo.objects.filter(user_id=uid).count()
       request.session['count'] = count_s
       #如果是ajax请求则返回json,否则转向购物车
       if request.is_ajax():
           # count=CartInfo.objects.filter(user_id=request.session['user_id']).count()
  
           print ('*'*10)
           print ('ajax')
           #--------------未使用
           return JsonResponse({'count':count_s})
       else:
           return redirect('/cart/')
  
   @islogin
   def edit(request,cart_id,count):
       try:
           cart=CartInfo.objects.get(pk=int(cart_id))
           count1=cart.count=int(count)
           cart.save()
           data={'ok':0}
       except Exception as e:
           data={'ok':count1}
       return JsonResponse(data)
  
   @islogin
   def delete(request,cart_id):
  
       # try:
       cart = CartInfo.objects.get(pk=int(cart_id))
       cart.delete()
       # print '*'*10
       # print ('delete')
       # data={'ok':1}
       # except Exception as e:
       count = CartInfo.objects.filter(user_id=request.session['user_id']).count()
       request.session['count'] = count
       data={'count':count}
       # print '*' * 10
       # print (count)
       return JsonResponse(data)