Python 如何在Django FormWizardView中显示基于百分比的学院列表

我有一个三页的表单列表，来自一个模型，我想在第二步根据百分比选择显示学院，但在第三步显示数据库中所有学院的列表

如何在Django FormWizardView中显示基于百分比的学院列表

这是我的型号。py

class Percentage(models.Model):
        number = models.CharField(max_length=100)

        def __str__(self):
            return self.number

    class College(models.Model):
        percentage = models.ForeignKey(Percentage, on_delete=models.CASCADE)
        name = models.CharField(max_length=30)

        def __str__(self):
            return self.name
class Student(models.Model):
    user=models.ForeignKey(User,on_delete=models.CASCADE)
    firstname = models.CharField(max_length=100,validators=[alphanumeric])

    lastname = models.CharField(max_length=100,validators=[alphanumeric])    
    image=models.ImageField(upload_to='files/%Y/%m/%d', blank=True)
    percentage = models.ForeignKey(Percentage, on_delete=models.SET_NULL, null=True)
    college = models.ForeignKey(College, on_delete=models.SET_NULL, null=True)

    description=models.TextField(blank=True)


    def __str__(self):
        return self.firstname

path('student/', StWizard.as_view([FirstForm, SecondForm, ThirdForm]), name='stwizards'),
    re_path(r'^stedit/(?P<id>\d+)/$', StWizard.edit_stwizard, name='edit_stwizard'),

forms.py

class FirstForm(forms.ModelForm):
        id = forms.IntegerField(widget=forms.HiddenInput, required=False)
        firstname = models.CharField(max_length=100,validators=[alphanumeric])

     class Meta:
        model = Student
        fields = ('firstname',)

class SecondForm(forms.ModelForm):  
    lastname = models.CharField(max_length=100,validators=[alphanumeric])    
    image = forms.ImageField(required=False)

    class Meta:
        model=Student
        fields=('lastname','image','percentage')

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

        self.fields['percentage'].widget.attrs={ 'id': 'percentage', 'label':'percentage',
                                                  'name': 'percentage'}


    def save(self, commit=True):
        user = super(SecondForm, self).save(commit=False)          
        user.percentage = self.cleaned_data['percentage']

        if commit:
            user.save()
        return user


class ThirdForm(forms.ModelForm):
    description = forms.CharField(widget=forms.Textarea)

    class Meta:
        model = Student
        fields = ('college','description',)

    def __init__(self, *args, **kwargs):
        super(ThirdForm, self).__init__(*args, **kwargs)
        self.fields['description'].widget.attrs={ 'id': 'id_description',
                                                  'class': 'myDescriptionClass',
                                                  'name': 'myDescriptionName',
                                                  'placeholder': 'myDescriptionholder'}
       self.fields['college'].widget.attrs = {'id': 'college', 'label': 'college'}

        if 'percentage' in self.data:
            try:

                percentage = int(self.data.get('percentage'))
                self.fields['college'].queryset = College.objects.filter(percentage=percentage).order_by('name') 

            except (ValueError, TypeError):

                pass  
        elif self.instance.pk:
            self.fields['college'].queryset = College.objects.none()
            self.fields['college'].queryset = self.instance.percentage.college_set.order_by('name')

class StWizard(SessionWizardView):
        template_name = "/stwizard_form.html"
        file_storage = DefaultStorage()
        #if you are uploading files you need to set FileSystemStorage
        def done(self, form_list, **kwargs):
            for form in form_list:
                print (form.initial)
            if not self.request.user.is_authenticated:
                raise Http404
            instance = Student()

            # moved for out of if
            for form in form_list:
                for field, value in form.cleaned_data.items():
                    setattr(instance, field, value)
            instance.user = self.request.user
            instance.save()

            return render_to_response('/stwizard_done.html', {
                'form_data': [form.cleaned_data for form in form_list], })


    def edit_stwizard(request, id):
        #get the object
        item = get_object_or_404(Student, pk=id)
        #make sure the item belongs to the user
        if item.user != request.user:
            raise HttpResponseForbidden()
        else:
            #get the initial data to include in the form
            initial = {'0': {'id': item.id,
                             'firstname': item.firstname,

            },
                       '1': {'lastname':item.lastname,
                             'image': item.image,
                             'percentage': item.percentage,

                       },
                       '2': {'college': item.college,
                           'description': item.description,
                       },
            }
            print (initial)
            form = StWizard.as_view([FirstForm, SecondForm, ThirdForm], initial_dict=initial)
            return form(context=RequestContext(request),request=request)


def load_colleges(request):
    percentage = request.GET.get('percentage')
    colleges = College.objects.filter(percentage=percentage).order_by('name')
    return render(request, '/college_dropdown_list_options.html', {'colleges': colleges})

视图.py

class FirstForm(forms.ModelForm):
        id = forms.IntegerField(widget=forms.HiddenInput, required=False)
        firstname = models.CharField(max_length=100,validators=[alphanumeric])

     class Meta:
        model = Student
        fields = ('firstname',)

class SecondForm(forms.ModelForm):  
    lastname = models.CharField(max_length=100,validators=[alphanumeric])    
    image = forms.ImageField(required=False)

    class Meta:
        model=Student
        fields=('lastname','image','percentage')

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

        self.fields['percentage'].widget.attrs={ 'id': 'percentage', 'label':'percentage',
                                                  'name': 'percentage'}


    def save(self, commit=True):
        user = super(SecondForm, self).save(commit=False)          
        user.percentage = self.cleaned_data['percentage']

        if commit:
            user.save()
        return user


class ThirdForm(forms.ModelForm):
    description = forms.CharField(widget=forms.Textarea)

    class Meta:
        model = Student
        fields = ('college','description',)

    def __init__(self, *args, **kwargs):
        super(ThirdForm, self).__init__(*args, **kwargs)
        self.fields['description'].widget.attrs={ 'id': 'id_description',
                                                  'class': 'myDescriptionClass',
                                                  'name': 'myDescriptionName',
                                                  'placeholder': 'myDescriptionholder'}
       self.fields['college'].widget.attrs = {'id': 'college', 'label': 'college'}

        if 'percentage' in self.data:
            try:

                percentage = int(self.data.get('percentage'))
                self.fields['college'].queryset = College.objects.filter(percentage=percentage).order_by('name') 

            except (ValueError, TypeError):

                pass  
        elif self.instance.pk:
            self.fields['college'].queryset = College.objects.none()
            self.fields['college'].queryset = self.instance.percentage.college_set.order_by('name')

class StWizard(SessionWizardView):
        template_name = "/stwizard_form.html"
        file_storage = DefaultStorage()
        #if you are uploading files you need to set FileSystemStorage
        def done(self, form_list, **kwargs):
            for form in form_list:
                print (form.initial)
            if not self.request.user.is_authenticated:
                raise Http404
            instance = Student()

            # moved for out of if
            for form in form_list:
                for field, value in form.cleaned_data.items():
                    setattr(instance, field, value)
            instance.user = self.request.user
            instance.save()

            return render_to_response('/stwizard_done.html', {
                'form_data': [form.cleaned_data for form in form_list], })


    def edit_stwizard(request, id):
        #get the object
        item = get_object_or_404(Student, pk=id)
        #make sure the item belongs to the user
        if item.user != request.user:
            raise HttpResponseForbidden()
        else:
            #get the initial data to include in the form
            initial = {'0': {'id': item.id,
                             'firstname': item.firstname,

            },
                       '1': {'lastname':item.lastname,
                             'image': item.image,
                             'percentage': item.percentage,

                       },
                       '2': {'college': item.college,
                           'description': item.description,
                       },
            }
            print (initial)
            form = StWizard.as_view([FirstForm, SecondForm, ThirdForm], initial_dict=initial)
            return form(context=RequestContext(request),request=request)


def load_colleges(request):
    percentage = request.GET.get('percentage')
    colleges = College.objects.filter(percentage=percentage).order_by('name')
    return render(request, '/college_dropdown_list_options.html', {'colleges': colleges})

向导\u form.html

{% block content %}
  <p> {{ wizard.steps. }}  {{ wizard.steps. }}</p>

  <form method="post" enctype="multipart/form-data" id="personFor" data-colleges-url="{% url 'ajax_load_colleges' %}"
                   >

      {% csrf_token %}

        <table>
              {{ wizard.management_form }}

              {% if wizard.form.forms %}
                {{ wizard.form.management_form }}
                {% for form in wizard.form.forms %}
                  {{ form }}
                {% endfor %}

              {% else %}
                {{ wizard.form|crispy }}
              {% endif %}
      </table><br>
          {% if wizard.steps.prev %}
          <button formnovalidate="formnovalidate" name="wizard_goto_step" type="submit" value="{{ wizard.steps.first }}">{% trans "first step" %}</button>
          <button formnovalidate="formnovalidate"  name="wizard_goto_step" type="submit" value="{{ wizard.steps.prev }}" >{% trans "prev step" %}</button>
          {% endif %}
      <input type="submit" value="submit" />
  </form>

{% endblock %}