用django做购物车，为什么购物车中相同的物品不能合并成一个？，django购物车,是根据这一个教程做的ht

用django做购物车，为什么购物车中相同的物品不能合并成一个？，django购物车,是根据这一个教程做的ht

是根据这一个教程做的
http://www.cnblogs.com/holbrook/archive/2012/03/02/2357343.html

view_cart.html

{% extends "base.html" %} {% block title %} 我的购物车{% endblock %} {% block pagename %} 我的购物车 {% endblock %} {% block content %}<div class="row">  <div class="span10">    <table class="condensed-table">      <thead>        <tr>          <th class="header">数量</th>          <th class="yellow header">名称</th>          <th class="blue header">单价</th>          <th class="green header">小计</th>        </tr>      </thead>      <tbody>        {% for item in cart.items %}        <tr>          <th>{{item.quantity}}</th>          <td>{{item.product.title}}</td>          <td>{{item.unit_price}}</td>          <td>{% widthratio item.quantity 1 item.unit_price %}</td>        </tr>        {% endfor %}        <tr>          <th></th>          <td></td>          <th>总计：</th>          <th>{{cart.total_price}}</th>          <th>数量：</th>          <th>{% for item in cart.items %}{{item.quantity}}{% endfor %}</th>        </tr>      </tbody>    </table>  </div>  <div class="span4">    <p><a class="btn primary span2" href="#">继续购物</a></a>    </p>    <p><a class="btn danger span2" href="{% url 'depotapp:clean_cart'%}">清空购物车</a>    </p>    <p><a class="btn success span2" href="#">结算</a>    </p>  </div></div>{% endblock %}

views.py :

def view_cart(request):    cart = request.session.get("cart",None)    t = get_template('depotapp/view_cart.html')    if not cart:        cart = Cart()        request.session["cart"] = cart    c = RequestContext(request,locals())    return HttpResponse(t.render(c))

models.py

class Cart(object):    def __init__(self, *args, **kwargs):        self.items = []        self.total_price = 0    def add_product(self,product):        self.total_price += product.price        for item in self.items:            if item.product.id == product.id:                item.quantity += 1        return self.items.append(LineItem(product=product,unit_price=product.price,quantity=1))    

编橙之家文章，