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 %}

  

    
        {% for item in cart.items %}
        
        {% endfor %}
        

      

        

          
数量
          
名称
          
单价
          
小计
        
      
      

          
{{item.quantity}}
          
{{item.product.title}}
          
{{item.unit_price}}
          
{% widthratio item.quantity 1 item.unit_price %}
        

          

          

          
总计：
          
{{cart.total_price}}
          
数量：
          
{% for item in cart.items %}{{item.quantity}}{% endfor %}
        
      
    
  

  

    
继续购物
    
    
清空购物车
    
    
结算
    
  


{% 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))