问Django表单域不显示

EN

<form method='POST' action="{% url 'set_profile_image' plant_pk=plnt.pk image_pk=img.pk %}">
    {% csrf_token %}
    <hr>
    {{ form.as_p }}
    <hr>
    <input type="submit" value="Submit">

class SetProfileImageForm(forms.ModelForm):
    """A form to set profile image."""
    image_main = forms.BooleanField(required=True)

    class Meta:
        model = Image
        fields = ["image_main","image_url",]

class SingleImageView(DetailView):
    """ A view to see a single image."""
    template_name = "project/single_image.html"
    queryset = Image.objects.all()

    def get_context_data(self, **kwargs):
        """Return a dictionary with context data for this template to use."""
        # get the default context data:
        # this will include the Profile record for this page view
        context = super(SingleImageView, self).get_context_data(**kwargs)

        img = Image.objects.get(pk=self.kwargs['image_pk'])
        plnt = Image.objects.get(pk=self.kwargs['image_pk']).plant
    
        context['img'] = img
        context['plnt'] = plnt
        form = SetProfileImageForm()
        context['set_profile_image'] = form

        # return the context dictionary
        return context

    def get_object(self):
        """Returns the Note Object that should be deleted."""
         # read the URL data values into variables
        plant_pk = self.kwargs['plant_pk']
        image_pk = self.kwargs['image_pk']

        # find the StatusMessage object, and return it
        return Image.objects.get(pk=image_pk)

    def set_profile_image(request, plant_pk, image_pk):
        """A custom view function to set profile image."""

    # find the plant for whom we are setting the image
    plant = Plant.objects.get(pk=plant_pk)

    if request.method == 'POST':
        if "cancel" in request.POST:
            return redirect('display_plant', pk=plant.pk)
    
        form = SetProfileImageForm(request.POST or None, request.FILES or None)
    
        if form.is_valid():

            plant.set_profile_image(image_pk)

            return redirect('display_plant', pk=plant.pk)

        else:
            print("Error: the form was not valid.")
    else:
        return reverse('gallery', kwargs={'pk':plant.pk})