Question

如何在表格中对一列Django元素进行排序？

我注意到Django Admin会这样做。怎么样？

我可以阅读任何网络资源吗？

*通过“Django元素”我指的是可插入的模板对象，如下所示：

{{ x.y }}

Answer 1

值得查看django admin中的ChangeList视图源代码：

http://code.djangoproject.com/svn/django/branches/releases/1.2.X/django/contrib/admin/views/main.py

订购流程大致如下：

您点击了管理员中的列标题，这会在网址中重新加载包含相关订单参数的页面，可在request.GET
此订单参数在ChangeList视图中解析：

self.order_field，self.order_type = self.get_ordering（）
queryset：

self.query_set = self.get_query_set（）特别是，函数中的以下行：如果self.order_field： qs = qs.order_by（'％s％s'％（（self.order_type =='desc'和' - '或''），self.order_field））

在理解源代码的同时使用django admin是我认为学习django的最好方法之一！

Answer 2

如果您是从查询中获取的，请在视图中使用order_by()方法。如果是列表，则在视图中使用sort()方法。

Answer 3

在查看管理员如何在Django 0.96中执行操作后，我创建了这个实用程序类。

它根据GET参数处理order_by条件的创建，并提供用于生成表标题排序链接的上下文变量，这些链接遵循当前排序字段和方向，当相同标题再次排序时反转方向

ORDER_VAR = 'o'
ORDER_TYPE_VAR = 'ot'

class SortHeaders:
    """
    Handles generation of an argument for the Django ORM's
    ``order_by`` method and generation of table headers which reflect
    the currently selected sort, based on defined table headers with
    matching sort criteria.

    Based in part on the Django Admin application's ``ChangeList``
    functionality.
    """
    def __init__(self, request, headers, default_order_field=None,
            default_order_type='asc', additional_params=None):
        """
        request
            The request currently being processed - the current sort
            order field and type are determined based on GET
            parameters.

        headers
            A list of two-tuples of header text and matching ordering
            criteria for use with the Django ORM's ``order_by``
            method. A criterion of ``None`` indicates that a header
            is not sortable.

        default_order_field
            The index of the header definition to be used for default
            ordering and when an invalid or non-sortable header is
            specified in GET parameters. If not specified, the index
            of the first sortable header will be used.

        default_order_type
            The default type of ordering used - must be one of
            ``'asc`` or ``'desc'``.

        additional_params:
            Query parameters which should always appear in sort links,
            specified as a dictionary mapping parameter names to
            values. For example, this might contain the current page
            number if you're sorting a paginated list of items.
        """
        if default_order_field is None:
            for i, (header, query_lookup) in enumerate(headers):
                if query_lookup is not None:
                    default_order_field = i
                    break
        if default_order_field is None:
            raise AttributeError('No default_order_field was specified and none of the header definitions given were sortable.')
        if default_order_type not in ('asc', 'desc'):
            raise AttributeError('If given, default_order_type must be one of \'asc\' or \'desc\'.')
        if additional_params is None: additional_params = {}

        self.header_defs = headers
        self.additional_params = additional_params
        self.order_field, self.order_type = default_order_field, default_order_type

        # Determine order field and order type for the current request
        params = dict(request.GET.items())
        if ORDER_VAR in params:
            try:
                new_order_field = int(params[ORDER_VAR])
                if headers[new_order_field][1] is not None:
                    self.order_field = new_order_field
            except (IndexError, ValueError):
                pass # Use the default
        if ORDER_TYPE_VAR in params and params[ORDER_TYPE_VAR] in ('asc', 'desc'):
            self.order_type = params[ORDER_TYPE_VAR]

    def headers(self):
        """
        Generates dicts containing header and sort link details for
        all defined headers.
        """
        for i, (header, order_criterion) in enumerate(self.header_defs):
            th_classes = []
            new_order_type = 'asc'
            if i == self.order_field:
                th_classes.append('sorted %sending' % self.order_type)
                new_order_type = {'asc': 'desc', 'desc': 'asc'}[self.order_type]
            yield {
                'text': header,
                'sortable': order_criterion is not None,
                'url': self.get_query_string({ORDER_VAR: i, ORDER_TYPE_VAR: new_order_type}),
                'class_attr': (th_classes and ' class="%s"' % ' '.join(th_classes) or ''),
            }

    def get_query_string(self, params):
        """
        Creates a query string from the given dictionary of
        parameters, including any additonal parameters which should
        always be present.
        """
        params.update(self.additional_params)
        return '?%s' % '&amp;'.join(['%s=%s' % (param, value) \
                                     for param, value in params.items()])

    def get_order_by(self):
        """
        Creates an ordering criterion based on the current order
        field and order type, for use with the Django ORM's
        ``order_by`` method.
        """
        return '%s%s' % (
            self.order_type == 'desc' and '-' or '',
            self.header_defs[self.order_field][1],
        )

示例视图：

from somewhere import SortHeaders
from django.contrib.auth.models import User
from django.shortcuts import render_to_response

LIST_HEADERS = (
    ('Username', 'username'),
    ('First Name', 'first_name'),
    ('Last Name', 'last_name'),
    ('Email', None),
)

def user_list(request):
    sort_headers = SortHeaders(request, LIST_HEADERS)
    users = User.objects.order_by(sort_headers.get_order_by())
    return render_to_response('users/user_list.html', {
        'users': users,
        'headers': list(sort_headers.headers()),
    })

示例模板（users/user_list.html）：

{% load my_tags %}
<table cellspacing="0">
<thead>
  <tr>
{% table_header headers %}
  </tr>
</thead>
<tbody>
  {% for user in users %}<tr class="{% cycle odd,even %}">
    <td><a href="{{ user.get_absolute_url }}">{{ user.username }}</a></td>
    <td>{{ user.first_name }}</td>
    <td>{{ user.last_name }}</td>
    <td>{{ user.email }}</td>
  </tr>
  {% endfor %}
</tbody>
</table>

示例包含标记（templatetags/my_tags.py）：

from django import template

def table_header(context, headers):
    return {
        'headers': headers,
    }

register = template.Library()
register.inclusion_tag('table_header.html', takes_context=True)(table_header)

样本包含标记模板（table_header.html）：

{% for header in headers %}<th{{ header.class_attr }}>
  {% if header.sortable %}<a href="{{ header.url }}">{% endif %}
  {{ header.text }}
  {% if header.sortable %}</a>{% endif %}
</th>{% endfor %}

如何在表格中对一列Django元素进行排序？

3 个答案: