Question

我整天都在努力。我正在尝试提出一种解决方案，以一种形式保存多张图片。我感觉自己很忙，但是现在的问题是，我一生都无法在提交表单时让ForeignKey自动分配。除了未将FK应用于数据库记录之外，以下代码在所有方面均起作用。任何帮助将不胜感激！

尝试通过：

FA_Attachments.objects.create(
                    image=f,field_evaluations = request.POST.get('order'))

只要给我：

Cannot assign "'test'": "FA_Attachments.field_evaluation" must be a "FieldEvaluation" instance.

Models.py

from django.db import models


class FieldEvaluation(models.Model):
    "Our default field evaluation form"
    created_at = models.DateTimeField(auto_now_add=True)
    order = models.CharField(max_length=50)


class FA_Attachments(models.Model):
    field_evaluation = models.ForeignKey(
        FieldEvaluation, on_delete=models.CASCADE, null=True)
    image = models.ImageField(upload_to='photos')

Forms.py

from django import forms
from .models import FieldEvaluation, FA_Attachments


class FieldEvaluationForm(forms.ModelForm):
    class Meta:
        model = FieldEvaluation
        fields = ['order']  # not attachments!

    attachments = forms.ImageField(
        widget=forms.ClearableFileInput(attrs={'multiple': True}))

Views.py

from django.views.generic.edit import CreateView
from django.shortcuts import render
from .forms import *
from .models import *


class FieldEvaluationView(CreateView):
    model = FieldEvaluation
    form_class = FieldEvaluationForm
    template_name = 'QA.html'
    success_url = '?success'

    def post(self, request, *args, **kwargs):
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        files = request.FILES.getlist('attachments')
        if form.is_valid():
            for f in files:
                FA_Attachments.objects.create(
                    image=f)
            return self.form_valid(form)
        else:
            return self.form_invalid(form)

Answer 1

您不保存ForeignKey！

首先，我建议您将附件关系设为必填项：

class FA_Attachments(models.Model):
    field_evaluation = models.ForeignKey(
        FieldEvaluation, on_delete=models.CASCADE)
    image = models.ImageField(upload_to='photos')

我删除了null=True，因为此模型与FieldEvaluation紧密相关

然后，您必须修改POST。

class FieldEvaluationView(CreateView):
    model = FieldEvaluation
    form_class = FieldEvaluationForm
    template_name = 'QA.html'
    success_url = '?success'

    def post(self, request, *args, **kwargs):
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        files = request.FILES.getlist('attachments')

        # your form must have it!
        order = request.POST.get('order')
        fe = FieldEvaluation.objects.create(order=order)

        if form.is_valid():
            for f in files:
                # here you create the relation with the FieldEvaluation
                FA_Attachments.objects.create(
                    image=f, field_evaluation=fe)
            return self.form_valid(form)
        else:
            return self.form_invalid(form)

Answer 2

我会使用覆盖form_valid而不是post方法。在form_valid中，您可以保存field_evaluation对象，然后可以将此新对象分配给ForeignKey字段。最后，您调用并返回form_valid（以form作为参数）。

class FieldEvaluationView(CreateView):
        model = FieldEvaluation
        form_class = FieldEvaluationForm
        template_name = 'QA.html'
        success_url = '?success'

        def form_valid(self, form):
            field_evaluation_obj = form.save(commit=True)
            files = self.request.FILES.getlist('attachments')
            for f in files:
                FA_Attachments.objects.create(image=f, field_evaluation=field_evaluation_obj)
            return super(FieldEvaluationView, self).form_valid(form)

用Django的CreateView分配外键

2 个答案: