Django：将变量从post传递到get_context_data（）

Question

我想将值从邮政表格传递到get_context_data函数。但是问题是，当我在post函数中使用该值时，它会打印正确的值，例如：self.start_date，但我在get_context_data中打印的却是None。当我删除此行start_date = None时，它给出了错误'JobListView' object has no attribute 'start_date'。

class JobListView(LoginRequiredMixin, generic.TemplateView):
    template_name = 'admin/jobs/job.html'

    # if i remove this then i get error 'JobListView' object has no attribute 'start_date'
    start_date = None

    def get_context_data(self, **kwargs):   
        context = super(JobListView, self).get_context_data(**kwargs)
        company_name = self.request.user.userprofile.user_company
        context['jobs'] = Jobs.objects.exclude(job_is_deleted = True)
        context['form'] = JobSearchForm()

        print(self.start_date) # this print as None

        return context

    def post(self, request, *args, **kwargs):
        self.start_date = self.request.POST.get('start_date',None)

        print(self.start_date) # this print correct value from form

        return HttpResponseRedirect('/useradmin/job/')