python - 如何从多个上下文对象中选择 get_context_data 分页?
问题描述
我正在尝试通过从多个上下文对象中进行选择来对 view.py 中的 get_context_data 进行分页。代码示例条件语句中只显示了两个选择,但我还有几个选择,基本上涵盖了表单提交的所有选择。然而,最后只返回一个上下文,将上下文传递给模板视图进行分页。
我还尝试在 settings.py 中全局设置分页,但它不起作用。
我之前看过下面的文章,作为获取上下文对象的分页指南。
从views.py:
from django.shortcuts import render
import django.views.generic
from django.http import HttpResponse
from django.template import loader
from django.template import RequestContext
from ephemera.models import *
from ephemera.serializers import ItemSerializer
from rest_framework import generics
from ephemera.forms import SearchForm, AdvSearchForm
from itertools import chain
from django.core.paginator import Paginator
from django.core.paginator import EmptyPage
from django.core.paginator import PageNotAnInteger
class SearchResultsAdvancedView(django.views.generic.ListView):
template_name = 'ephemera/searchresults_advanced.html'
form = AdvSearchForm()
paginate_by = 10
model = Item
def get_context_data(self, **kwargs):
context = super(SearchResultsAdvancedView, self).get_context_data(**kwargs)
choose_collection = self.request.GET.get('choose_collection')
user_input = self.request.GET.get('user_input')
choose_item = self.request.GET.get('choose_item')
bookpage = False
imagepage = False
if choose_collection == 'All' and user_input == '' and choose_item == 'book':
context['book_qs'] = Item.objects.raw('SELECT * FROM ephemera_item WHERE ephemera_item.material_type LIKE %s', ['book']);
bookpage = True
elif choose_collection == 'All' and user_input == '' and choose_item == 'image':
context['image_qs'] = Item.objects.raw('SELECT * FROM ephemera_item WHERE ephemera_item.material_type LIKE %s', ['image']);
imagepage = True
if bookpage:
paginator = Paginator(context, self.paginate_by)
page = self.request.GET.get('page')
try:
book_qs = paginator.page(page)
except PageNotAnInteger:
book_qs = paginator.page(1)
except EmptyPage:
book_qs = paginator.page(paginator.num_pages)
context['book_qs'] = book_qs
elif imagepage:
paginator = Paginator(context, self.paginate_by)
page = self.request.GET.get('page')
try:
image_qs = paginator.page(page)
except PageNotAnInteger:
image_qs = paginator.page(1)
except EmptyPage:
image_qs = paginator.page(paginator.num_pages)
context['image_qs'] = image_qs
return context
返回的错误包括:
异常值:不可散列类型:'slice'
异常位置:c:\users\administrator\appdata\local\programs\python\python36-32\lib\site-packages\django\core\paginator.py 页面第 70 行
解决方案
此处无需使用get_context_data
[Django-doc],您可以覆盖get_queryset
[Django-doc]和get_context_object_name
[Django-doc]来确定模板中列表的名称:
class SearchResultsAdvancedView(django.views.generic.ListView):
template_name = 'ephemera/searchresults_advanced.html'
form = AdvSearchForm()
paginate_by = 10
model = Item
def item_type(self):
choose_collection = self.request.GET.get('choose_collection')
if choose_collection != 'All' or not self.request.GET.get('user_input'):
return None
choose_item = self.request.GET.get('choose_item')
if choose_item in ('book', 'image'):
return choose_item
return None
def get_queryset(self, *args, **kwargs):
item_type = self.get_item_type()
qs = super.get_queryset(*args, **kwargs)
if item_type is not None:
return qs.filter(material_type__iexact=item_type)
return qs.none()
def get_context_object_name(self, object_list):
item_type = self.get_item_type()
if item_type is not None:
return '{}_qs'.format(item_type)
return super().get_context_object_name(object_list)
Django 的逻辑会对QuerySet
自身进行分页,因此您无需担心这一点。这是由于get_context_data
[Django-doc] 的 [Django-doc MultipleObjectMixin
]实现:
def get_context_data(self, *, object_list=None, **kwargs): """Get the context for this view.""" queryset = object_list if object_list is not None else self.object_list page_size = self.get_paginate_by(queryset) context_object_name = self.get_context_object_name(queryset) if page_size: paginator, page, queryset, is_paginated = self.paginate_queryset(queryset, page_size) context = { 'paginator': paginator, 'page_obj': page, 'is_paginated': is_paginated, 'object_list': queryset } else: context = { 'paginator': None, 'page_obj': None, 'is_paginated': False, 'object_list': queryset } if context_object_name is not None: context[context_object_name] = queryset context.update(kwargs) return super().get_context_data(**context)
话虽如此,我的印象是建模做得不太好。ItemType
如果您有项目类型,则定义模型是有意义的。此外,您最好使用 Django 的 ORM 来生成查询而不是原始查询。
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