django - 初学者 : Dynamic filtering of foreign key field in Django CreateView form

Question

模型:

class Instructional_Cycle(models.Model):
    date_started = models.DateField()
    date_finished = models.DateField()
    standard_tested = models.OneToOneField(Standard, on_delete=models.CASCADE)

class Standard(models.Model):
    subject = models.CharField(max_length=14, choices=subjects)
    grade_level = models.IntegerField(choices=gradeLevels)
    descriptor = models.CharField(max_length=15)
    description = models.TextField()
    essential_status = models.BooleanField(default=False)

查看:

class CycleCreateView(CreateView):
    model = Instructional_Cycle
    template_name = 'cycle_new.html'
    fields = '__all__'
    success_url = reverse_lazy('student_progress:cycles')

模板:

<!-- student_progress/cycle_new.html -->

{% extends 'base.html' %}

{% block content %}
    <h1>Add a new instructional cycle:</h1>

    <form action="{% url 'student_progress:cycle_new' %}" method="post">
        {% csrf_token %}
        {{ form.as_p }}
        <button name="submit">add cycle</button>
    </form>

{% endblock content %}

我在使用此表单时遇到的问题是，选择 Instructional_Cycle.standard_tested 的下拉菜单实际上有 1000 条来自 Standard 的记录。用户无法滚动浏览所有这些并找到他们想要的一条记录。

我需要的是单击链接并按主题或等级级别和/或搜索框过滤下拉列表的方法，类似于通过在 admin.py 中创建自定义管理模型在管理端实现的效果，如下所示:

class StandardAdmin(admin.ModelAdmin):
    list_display = ('descriptor', 'description', 'essential_status')
    list_filter = ('subject', 'grade_level', 'essential_status')
    search_fields = ('descriptor',)
    inlines = [MilestoneInLine]

    def get_search_results(self, request, queryset, search_term):
        queryset, use_distinct = super().get_search_results(request, queryset,         search_term)
        try:
            search_term_as_int = int(search_term)
        except ValueError:
            pass
        else:
            queryset |= self.model.objects.filter(age=search_term_as_int)
        return queryset, use_distinct

请为这个新手“降低难度”。我刚刚完成了 Django for Beginners 的工作，而我关于这一切如何组合在一起的概念模型仍然充满漏洞。请假设我几乎什么都不知道。谢谢!

Answer 1

页面上的大量响应式工作将要求您熟悉 Javascript、Ajax 等。如果是这种情况，您可以采用多种方法来使用所需的选项刷新表单。

或者，您可以在流程的前一步向用户询问必要的数据，让 Django 首先为您构建正确的表单 overriding the form's default queryset .