通过 Django 中的模型表单保存多对多数据 [英] Saving Many To Many data via a modelform in Django

问题描述

我在从表单中保存多对多字段时遇到问题.这是我的模型:

I have a problem saving many to many fields from a form. Here are my models:

class TextIssue(models.Model):
    Issue = models.CharField(max_length=150, unique=True)

    def __unicode__(self):
        return self.Issue

class PadIssue(models.Model):
    Issue = models.CharField(max_length=150, unique=True)

    def __unicode__(self):
        return self.Issue   


class PHIssue(models.Model):
    Data = models.ForeignKey(Data)
    TextIssue = models.ManyToManyField(TextIssue, blank=True, null=True)
    PadIssue = models.ManyToManyField(PadIssue, blank=True, null=True)
    Notes = models.TextField()

    def clean(self):
        from django.core.exceptions import ValidationError
        if self.TextIssue is None and self.PadIssue is None:
            raise ValidationError('You must choose at least one issue category.')   

        if self.Notes is None:
            raise ValidationError('You must write a note regarding the issues selected above.')


class PHIssueForm(ModelForm):

    class Meta:
        model = PHIssue
        exclude = ('Data',)

这里我在我的 views.py 中处理 post 请求:

And here I process the post request in my views.py:

def process_npiform(request, npi_id=None):

    if npi_id:

        try:
            npi = Data.objects.get(id=int(npi_id))
        except: 

            raise Http404   

    if request.method == 'POST':
        data = DataForm(request.POST, instance=npi, prefix='npi_data')

        if data.is_valid():
            update = data.save(commit=False)

            if not request.user.is_superuser:
                update.User = request.user

            update.save()

            if update.Status == 'past-due':

                try:
                    prefab = PHIssue.objects.get(Data=npi)

                except:
                    prefab = PHIssue(Data=Data.objects.get(id=int(update.id)))
                    prefab.save()

                issue = PHIssueForm(request.POST, instance=prefab, prefix='npi_issue')

                if issue.is_valid():

                    save_issue = issue.save(commit=False)

                    save_issue.save()




            return HttpResponseRedirect(reverse('pm'))

        else:
            return render_to_response('npi/data.html', {'data': data, 'issue': issue}, context_instance=RequestContext(request))    
    else:
        return HttpResponseRedirect(reverse('pm'))

每当我通过表单保存时，PHIssue 实例中只会保存 Notes 文本字段，而多对多字段则留空.有人可以帮我找出问题所在吗?

Whenever I save through the form, only the Notes text field gets saved in the PHIssue instance, and the many to many fields are left blank. Can someone help me find what is wrong?

推荐答案

http://docs.djangoproject.com/en/dev/topics/forms/modelforms/#the-save-method

使用commit=False时，必须调用save_m2m()

m2m 关系需要先保存父对象，而使用 commit=False

m2m relationships require the parent object to be saved first, which you are not doing by using commit=False

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