在Django模板中将CheckboxSelectMultiple分组

Question

如何CheckboxSelectMultiple对相关模型产生的复选框进行分组？

这是最好的例子。

models.py：

class FeatureCategory(models.Model):
    name = models.CharField(max_length=30)

class Feature(models.Model):
    name = models.CharField(max_length=30)
    category = models.ForeignKey(FeatureCategory)

class Widget(models.Model):
    name = models.CharField(max_length=30)
    features = models.ManyToManyField(Feature, blank=True)

forms.py：

class WidgetForm(forms.ModelForm):
    features = forms.ModelMultipleChoiceField(
        queryset=Feature.objects.all(),
        widget=forms.CheckboxSelectMultiple,
        required=False
    )
    class Meta:
        model = Widget

views.py：

def edit_widget(request):
    form = WidgetForm()
    return render(request, 'template.html', {'form': form})
template.html：

{{ form.as_p }}

上面产生了以下输出：

[] Widget 1
[] Widget 2
[] Widget 3
[] Widget 1
[] Widget 2

我想要按功能类别（基于ForeignKey）对功能复选框进行分组：

Category 1:
  [] Widget 1
  [] Widget 2
  [] Widget 3

Category 2:
  [] Widget 1
  [] Widget 2

我该如何实现？我尝试使用{% regroup %}模板标签无济于事。

任何建议，不胜感激。

Answer 1

你必须编写自定义CheckboxSelectMultiple窗口小部件。通过使用代码段，我尝试通过将CheckboxSelectMultiplefield category_name作为属性添加到字段中以使字段可迭代attrs。这样我以后可以regroup在模板中使用标记。

下面的代码根据你的需要从代码段中进行了修改，显然可以使此代码更简洁，更通用，但是目前还不是通用的。

forms.py

from django import forms
from django.forms import Widget
from django.forms.widgets import SubWidget
from django.forms.util import flatatt
from django.utils.html import conditional_escape
from django.utils.encoding import StrAndUnicode, force_unicode
from django.utils.safestring import mark_safe

from itertools import chain
import ast

from mysite.models import Widget as wid # your model name is conflicted with django.forms.Widget
from mysite.models import Feature

class CheckboxInput(SubWidget):
    """
    An object used by CheckboxRenderer that represents a single
    <input type='checkbox'>.
    """
    def __init__(self, name, value, attrs, choice, index):
        self.name, self.value = name, value
        self.attrs = attrs
        self.choice_value = force_unicode(choice[1])
        self.choice_label = force_unicode(choice[2])

        self.attrs.update({'cat_name': choice[0]})

        self.index = index

    def __unicode__(self):
        return self.render()

    def render(self, name=None, value=None, attrs=None, choices=()):
        name = name or self.name
        value = value or self.value
        attrs = attrs or self.attrs

        if 'id' in self.attrs:
            label_for = ' for="%s_%s"' % (self.attrs['id'], self.index)
        else:
            label_for = ''
        choice_label = conditional_escape(force_unicode(self.choice_label))
        return mark_safe(u'<label%s>%s %s</label>' % (label_for, self.tag(), choice_label))

    def is_checked(self):
        return self.choice_value in self.value

    def tag(self):
        if 'id' in self.attrs:
            self.attrs['id'] = '%s_%s' % (self.attrs['id'], self.index)
        final_attrs = dict(self.attrs, type='checkbox', name=self.name, value=self.choice_value)
        if self.is_checked():
            final_attrs['checked'] = 'checked'
        return mark_safe(u'<input%s />' % flatatt(final_attrs))

class CheckboxRenderer(StrAndUnicode):
    def __init__(self, name, value, attrs, choices):
        self.name, self.value, self.attrs = name, value, attrs
        self.choices = choices

    def __iter__(self):
        for i, choice in enumerate(self.choices):
            yield CheckboxInput(self.name, self.value, self.attrs.copy(), choice, i)

    def __getitem__(self, idx):
        choice = self.choices[idx] # Let the IndexError propogate
        return CheckboxInput(self.name, self.value, self.attrs.copy(), choice, idx)

    def __unicode__(self):
        return self.render()

    def render(self):
        """Outputs a <ul> for this set of checkbox fields."""
        return mark_safe(u'<ul>\n%s\n</ul>' % u'\n'.join([u'<li>%s</li>'
                % force_unicode(w) for w in self]))

class CheckboxSelectMultipleIter(forms.CheckboxSelectMultiple):
    """
    Checkbox multi select field that enables iteration of each checkbox
    Similar to django.forms.widgets.RadioSelect
    """
    renderer = CheckboxRenderer

    def __init__(self, *args, **kwargs):
        # Override the default renderer if we were passed one.
        renderer = kwargs.pop('renderer', None)
        if renderer:
            self.renderer = renderer
        super(CheckboxSelectMultipleIter, self).__init__(*args, **kwargs)

    def subwidgets(self, name, value, attrs=None, choices=()):
        for widget in self.get_renderer(name, value, attrs, choices):
            yield widget

    def get_renderer(self, name, value, attrs=None, choices=()):
        """Returns an instance of the renderer."""

        choices_ = [ast.literal_eval(i[1]).iteritems() for i in self.choices]
        choices_ = [(a[1], b[1], c[1]) for a, b, c in choices_]

        if value is None: value = ''
        str_values = set([force_unicode(v) for v in value]) # Normalize to string.
        if attrs is None:
            attrs = {}
        if 'id' not in attrs:
            attrs['id'] = name
        final_attrs = self.build_attrs(attrs)
        choices = list(chain(choices_, choices))
        return self.renderer(name, str_values, final_attrs, choices)

    def render(self, name, value, attrs=None, choices=()):
        return self.get_renderer(name, value, attrs, choices).render()

    def id_for_label(self, id_):
        if id_:
            id_ += '_0'
        return id_

class WidgetForm(forms.ModelForm):
    features = forms.ModelMultipleChoiceField(
        queryset=Feature.objects.all().values('id', 'name', 'category__name'),
        widget=CheckboxSelectMultipleIter,
        required=False
    )
    class Meta:
        model = wid

然后在模板中：

{% for field in form %}
{% if field.name == 'features' %} 
    {% regroup field by attrs.cat_name as list %}

    <ul>
    {% for el in list %}
        <li>{{el.grouper}}
        <ul>
            {% for e in el.list %}
                {{e}} <br />
            {% endfor %}
        </ul>
        </li>
    {% endfor %}
    </ul>
{% else %}
    {{field.label}}: {{field}}
{% endif %}

{% endfor %}

结果：我在类别表中添加了国家名称，在功能表中添加了城市名称，因此在模板中，我能够根据国家（类别）对城市（功能）进行重新分组