使用ModelForm和ModelMultipleChoiceField保存为ManyToManyFields

Question

我创建了一个基本的Django应用程序，其中包含书籍/作者/出版商按照Django的书-试图使用一个ModelForm来创建一种方法来修改现有的书籍-问题是，"作者"字段是一个ManyToManyField，当我选择ModelForm上的一个选择，它只是擦除现有的选择，不保存新的?

models.py

class Book(models.Model):
    title = models.CharField(max_length=100)
    authors = models.ManyToManyField2(Author)
    publisher = models.ForeignKey(Publisher)
    publication_date = models.DateField()
    def __unicode__(self):
        return self.title
class BookForm(ModelForm):
    class Meta:
        model = Book
    authors = forms.ModelMultipleChoiceField(queryset=Author.objects.all(), required=False)

views.py

def editBook(request, b=None):
    instance = None
    if b is not None:
        instance = Book.objects.get(title=b)
    if request.method == 'POST':
        form = BookForm(request.POST, instance=instance)
        if form.is_valid():
            form.save()
            return HttpResponseRedirect('/contact/thanks/')
    else:
        form = BookForm(instance=instance)
    return render_to_response('book_form.html', {'form':form})

干杯!

编辑我刚刚在views.py

中找到了几篇鼓励以下内容的文章

authors = form.save(commit=False)
authors.user = request.user
authors.save()
form.save_m2m()

但仍然没有任何运气-不可能这么难!

Answer 1

解决方案是重写ModelForm中的save方法:

def save(self, commit=True):
    authors =[]
    for a in self.cleaned_data['authors']:
         authors.append(Author.objects.get(first_name=t.first_name))
    b = super(BookForm, self).save(commit=commit)
    for a in authors:
        b.authors.add(a)
    b.save()

Answer 2

因为您覆盖了authors字段。要么不做，让Django来做，要么手动处理。