Question

我正在django上实现csv export。特别是我在我的模板上有一个链接来导出实际的查询，为此我试图在同一个基于类的视图上处理所有。

这是我的代码

@Resource
MyService myService;



@Resource
MyService myService2;

但是方法csv_output（）是错误的..我得到这个TypeError：csv_output（）接受0位置参数但是给出了1

我也尝试过使用classmethod装饰器，但没有成功。

我的问题是：如何从同一个类的另一个方法访问queryset变量？

Answer 1

请注意self中的get_queryset(self)。这意味着此方法的第一个参数始终是类的实例（在您的情况下，MyView）。所以当你想用另一种方法调用它时，你应该提供这个实例。

解决方案是将@staticmethod装饰器替换为@classmethod一个：

class MyView(ListView):  
    template_name = 'my_template.html'  
    model = Archivio  

    def get_queryset(self):
        if self.request.GET.get('q'):  
            dateC = '01/01/' + self.request.GET.get('q')          
            queryset = Archivio.objects.filter(~Q(quoteiscrizione__anno_quota__exact=self.request.GET.get('q'))  

            return queryset

    @classmethod  
    def csv_output(cls):
        qs = cls.get_queryset(cls)

        # Class methods have one required positional argument
        # which is the class that contains them

        # They are called like this:
        # MyClass.class_method()

        # So in your case, you can call
        # get_queryset() by doing MyView.get_queryset()

        # But as you are in a class method, you do
        # cls.get_queryset()

        # As get_queryset() needs one positional argument *self*,
        # which is the instance of your class, you do
        # cls.get_queryset(cls)

        # and it will work as expected :-)

Answer 2

我解决了我的问题，在请求中保存了我的查询集，然后在我的视图上使用它，如下所示：

views.py
class SomeClass(ListView):
    def get_queryset(self):
        .....
        queryset = MyModel.objects.filter(*somefilterlist)
        self.request.session['search_queryset'] = serialize('json', queryset) # in order to save something on session in must be JSON serialized

class Output(SomeClass):
    @classmethod
    def cvsOutput(cls):
        deserialized = list(deserialize('json', request.session.get('search_queryset')))
        pk_list = []
        for arch in deserialized:
            pk_list.append(arch.object.pk) # List of pk

        queryset = Archivio.objects.filter(pk__in=pk_list) # Query the list ok pk's

通过这种方式，我能够提供ListView查询集的列表ok pk，然后根据pk的列表重新生成相同的查询..

Django在同一视图上从自定义方法访问queryset变量

2 个答案: