从Django中检索的模型对象访问属性

Question

I am trying to access an attribute from a model object that I passed to my class. So I have my view doing something like:

my_events = Event.objects.order_by('start').filter(start__year=year, start__month=month)

and then I pass that to my class like so:

calendar = EventCalendar(my_events).formatmonth(year, month)

and then here is my class

# -*- coding: UTF-8 -*-
from calendar import HTMLCalendar
from datetime import date
from itertools import groupby
from django.utils.html import conditional_escape as esc


class EventCalendar(HTMLCalendar):

    def __init__(self, event):
        super(EventCalendar, self).__init__()
        self.event = self.group_by_day(event)

    def formatday(self, day, weekday):
        if day != 0:
            cssclass = self.cssclasses[weekday]


            if date.today() == date(self.year, self.month, day):
                cssclass += ' today'
            if day in self.event:
                cssclass += ' filled'
                extra_div = ['<div class="event_container"><ul>']
                for event in self.event[day]:
                    extra_div.append('<li>')
                    extra_div.append('<a href="%s">' % event.get_absolute_url())
                    extra_div.append(esc(event.title))
                    extra_div.append('</a></li>')
                extra_div.append('</ul></div>') #END event_container

                #Custom div wrapper
                extra_div.append('<div class="extra_container">')

                #Custom div add_event
                extra_div.append('<div class="add_event">')
                extra_div.append('<a href="#">add event</a>')
                extra_div.append('</div>')

                #Custom div show_day
                extra_div.append('<div class="show_day">')
                extra_div.append('<a href="#">show day</a>')
                extra_div.append('</div>')

                extra_div.append('</div>') #END extra_container

                return self.day_cell(cssclass, '%d %s' % (day, ''.join(extra_div)))

            #Custom div wrapper
            extra_div = ['<div class="extra_container">']

            #Custom div add_event
            extra_div.append('<div class="add_event">')
            extra_div.append('<a href="#">add event</a>')
            extra_div.append('</div>')

            #Custom div show_day
            extra_div.append('<div class="show_day">')
            extra_div.append('<a href="#">show day</a>')
            extra_div.append('</div>')

            extra_div.append('</div>')

            return self.day_cell(cssclass, '%d %s' % (day, ''.join(extra_div)))
        return self.day_cell('noday', '&nbsp;')

    def formatmonth(self, year, month):
        self.year, self.month = year, month
        return super(EventCalendar, self).formatmonth(year, month)

    def group_by_day(self, event):
        event_dict = {}
        start = event.start.day
        end = event.end.day
        return event_dict

    def day_cell(self, cssclass, body):
        return '<td class="%s">%s</td>' % (cssclass, body)

The issue is with the group_by_day(self, event) section in the code. I'm trying to retrieve the start and end day of my event. with:

start = event.start.day
end = event.end.day

But when I do that I get and error

'QuerySet' object has no attribute 'start'

Does this mean that when I retrieved the object I only got a reference to it, something like lazy instantiation ? Or am I just trying to access it wrong?

sorry if question is trivial, really new to python/django. Thanks

Answer 1

Event.objects.order_by('start').filter(start__year=year, start__month=month)

Returns a list of matching Event objects. You then pass this QuerySet list to:

group_by_day(self, event)

Which from your parameter names suggests you think you are passing a single event. So it doesn't work.