访问 CheckboxSelectMultiple 复选框的属性

Question

短版

在 Django 模板语言中，如何访问 CheckboxSelectMultiple 小部件中给定复选框的属性？

加长版

可以轻松访问典型 Django 小部件的属性：

{% for field in form %}
{{ field.widget.attrs.something }}
{% endfor %}

但是，此方法不适用于CheckboxSelectMultiple 小部件内的复选框。

我有一个自定义的 CheckboxSelectMultiple 小部件，我用它来显示 ManyToMany ModelForm 字段。自定义小部件为 create_option 方法中的每个复选框添加了额外的属性。

附加属性在输入元素的 HTML 中适当显示：

<input type="checkbox" name="questions" value="22" id="id_questions_12" category="Category Name" category_number="3" question="Question Name" question_number="4">

为了显示和组织表单字段，我需要访问这些附加属性。

Answer 1

在放置一周左右后，我又回到了这个问题。在玩了更多并阅读了BoundField（特别是BoundWidget）的文档之后，我发现了如何访问CheckboxSelectMultiple小部件中单个复选框的attrs：

{% for field in form %}
{% for check in field.subwidgets %}
{% for a in check.data.attrs %}

Answer 2

我能够使用this answer 中给出的相同技术。它非常适用于CheckboxSelectMultiple，尽管它没有在答案中使用。

我把它保存在我项目的forms.py：

from django.forms.widgets import CheckboxSelectMultiple, Select


class SelectWithAttrs(Select):
    """
    Select With Option Attributes:
        Subclass of Django's Select widget that allows attributes in options,
        e.g. disabled="disabled", title="help text", class="some classes",
             style="background: color;", etc.

    Pass a dict instead of a string for its label:
        choices = [ ('value_1', 'label_1'),
                    ...
                    ('value_k', {'label': 'label_k', 'foo': 'bar', ...}),
                    ... ]
    The option k will be rendered as:
        <option value="value_k" foo="bar" ...>label_k</option>
    """

    def create_option(self, name, value, label, selected, index,
                      subindex=None, attrs=None):
        if isinstance(label, dict):
            opt_attrs = label.copy()
            label = opt_attrs.pop('label')
        else:
            opt_attrs = {}
        option_dict = super().create_option(
            name, value, label, selected, index,
            subindex=subindex, attrs=attrs)
        for key, val in opt_attrs.items():
            option_dict['attrs'][key] = val
        return option_dict


class CheckboxSelectMultipleWithAttrs(
        SelectWithAttrs, CheckboxSelectMultiple):
    pass

这是我的一个项目中使用此示例的工作 sn-p。一开始的内容并不重要，但它展示了如何构建您的属性字典并将其传递给您的choices。

from django import forms
from django.whatever import other_stuff

from project_folder import forms as project_forms


class MyForm(forms.ModelForm):
    class Meta:
        model = MyModel
        fields = ['employees']

    def __init__(self, *args, **kwargs)
        super().__init__(*args, **kwargs)

        self.fields['employees'].queryset =\
            self.company.employee_set.filter(is_active=True)

        existing_crews_employees = []
        for crew in existing_job_crews:
            crew_employees =\
                [employee.__str__() for employee in crew.employees.all()]
            existing_crews_employees.append({'crew_name': crew.crewtype.name,
                                             'employees': crew_employees})

        employees_choices = []
        for (index, choice) in enumerate(self.fields['employees'].choices):
            # loop over each choice and set proper paramaters for employees
            # that are unassigned/on the current crew/on a different crew
            employee_in_crew = False

            employee_name = choice[1]
            for crew_and_employees in existing_crews_employees:
                for employee in crew_and_employees['employees']:
                    if employee_name == employee.__str__():
                        crew_name = crew_and_employees['crew_name']

                        if self.obj and self.obj.crewtype.name == crew_name:
                            # check the box if employee in current crew
                            employees_choices.append((choice[0], {
                                'label': choice[1],
                                'checked': True,
                                'id': f'id_employees_{choice[0].instance.id}'
                            }))
                        else:
                            # disable the choice if employee in another crew
                            employees_choices.append((choice[0], {
                                'label':
                                    employee_name + f" (on Crew: {crew_name})",
                                'disabled': True}))
                        employee_in_crew = True

            # for valid entries, ensure that we pass the proper ID
            # so that clicking the label will also check the box
            if not employee_in_crew:
                employees_choices.append((choice[0], {
                    'label': choice[1],
                    'id': f'id_employees_{choice[0].instance.id}'}))

        self.fields['employees'].widget = project_forms.CheckboxSelectMultipleWithAttrs(
            choices=employees_choices)

在使用此技术时要牢记两件重要的事情：

• 确保将 id 传递到您的 attrs 以获得可点击选项，否则您的标签在被点击时不会选中正确的框。
• 此方法当前需要使用新属性 dict 设置初始值。确保将 'checked': True 键值对传递给任何应选中的框。