Question

我一直在玩django创建一个资产管理应用程序，并在文件上传到模型实例行为方面遇到了障碍。我试图在Forms.py

中使用ModelForm类

基本上我非常确定form.save（）没有将我上传的文件写入磁盘来更新我的模型实例。我是否必须将form.save定义写入AssetForm？或者我错过了别的什么。

感谢任何帮助。

我的项目是围绕民意调查教程https://docs.djangoproject.com/en/1.8/intro/tutorial01/和Need a minimal Django file upload example的最小文件上传教程构建的。

这是我的模特.py

class Category(models.Model):
    category_text = models.CharField(max_length=200)
    def __str__(self):              # __unicode__ on Python 2
        return self.category_text

class Asset(models.Model):
    asset_text = models.CharField(max_length=200)
    asset_tag = models.CharField(max_length=200)
    asset_category = models.ForeignKey(Category)
    cert_date = models.DateTimeField('cert published')

    def __str__(self):              # __unicode__ on Python 2
        return self.asset_text
    def was_certed_recently(self):
        return self.cert_date >= timezone.now() - datetime.timedelta(days=365)
    was_certed_recently.admin_order_field = 'cert_date'
    was_certed_recently.boolean = True
    was_certed_recently.short_description = 'Certified recently?'
    docfile = models.FileField(upload_to='documents')

这是我的forms.py

from django import forms
from django.forms import ModelForm
from polls.models import Asset





class AssetForm(ModelForm):
    class Meta:
        model = Asset
        fields = '__all__'

这是我的views.py

# -*- coding: utf-8 -*-
from django.shortcuts import render_to_response
from django.template import RequestContext
from django.http import HttpResponseRedirect
from django.core.urlresolvers import reverse
from django.http import HttpResponse
#from django.template import RequestContext, loader
from django.shortcuts import get_object_or_404, render
from django.http import Http404 
from polls.models import Asset 
from polls.forms import AssetForm 

def list(request, asset_id):
    # Handle file upload
    ID = asset_id
    p = get_object_or_404(Asset, pk = asset_id)

    if request.method == 'POST':
        form = AssetForm(request.POST, request.FILES, instance= p )
        if form.is_valid():
            form.save()
            # Redirect to the document list after POST
            return HttpResponseRedirect(reverse('list', args=(p.id,)))

    else:
        form = AssetForm() # A empty, unbound form

    # Load documents for the list page
    documents = p



    # Render list page with the documents and the form
    return render_to_response(
        'polls/list.html', 
        {'documents': documents, 'ID': ID, 'form': form},
        context_instance=RequestContext(request )
    )



def index(request):
    latest_asset_list = Asset.objects.order_by('-cert_date')[:]
    context = {'latest_asset_list': latest_asset_list}
    return render(request, 'polls/index.html', context)

url.py

from django.conf.urls import  url
from . import views


urlpatterns = [
    #url(r'^/list/$', 'list', name='list'),
    url(r'^$', views.index, name='index'),
    # ex: /polls/5/
    url(r'^(?P<asset_id>[0-9]+)/$', views.list, name='list'),
    # ex: /polls/5/results/
    url(r'^(?P<asset_id>[0-9]+)/results/$', views.results, name='results'),
    # ex: /polls/5/vote/
    url(r'^(?P<asset_id>[0-9]+)/vote/$', views.vote, name='vote'),

]

最后是我的list.html模板

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title>Minimal Django File Upload Example</title>   
    </head>
    <body>
    <!-- List of uploaded documents -->
    {% if documents %}
        <ul>
            <p>Current Doc.</p>
            <li><a href="{{ documents.docfile.url }}">{{ documents.docfile.name }}</a></li>

        </ul>
    {% else %}
        <p>No documents.</p>
    {% endif %}

    <ul>



 {{ ID }} 



        <!-- Upload form. Note enctype attribute! -->
        <form action="{% url 'list' ID %}" method="post" enctype="multipart/form-data">


            {% csrf_token %}
            <p>{{ form.non_field_errors }}</p>
            <p>{{ form.docfile.label_tag }} {{ form.docfile.help_text }}</p>
            <p>
                {{ form.docfile.errors }}
                {{ form.docfile }}
            </p>
            <p><input type="submit" value="Upload" /></p>
        </form>
    </body>
</html>

Answer 1

你做了两次各种事情。例如，在您的函数开始时，您将资产转换为p，然后将相同的资产转换为a。为什么呢？

更重要的是，在is_valid()块中，您只是从上传的文件中创建一个新的Asset对象，而没有来自表单的其他数据，但是您保存了应该更新现有资产的表单本身。这可能是导致问题的原因 - 您应该使用docfile删除这些行，然后只保存表单。

django form.save（）无法在模型实例更新时写入磁盘

1 个答案: