django ManyToManyField保存

Question

有许多字段的表单(日期、字符、文本、图像、URL.)而且效果很好。我的意思是，值必须提交给DB。但是当我添加ManyToManyField时，它并没有将这个MultipleChoice表单的值保存到DB中。知道为什么吗？

models.py：

class EventTag(models.Model):
    tags = models.CharField(max_length=300)

    def __str__(self):
        return self.tags

class Article(models.Model):
    source = models.CharField(max_length=100)
    source_img = models.ImageField(default='default.png', blank=True)
    #other fields
    event_tags = models.ManyToManyField(EventTag, blank=True)

forms.py：

class CreateArticle(forms.ModelForm):
    class Meta:
        model = models.Article
        fields = ['source', 'source_img', 'event_tags', ]

views.py：

def article_create(request):
    if request.method == 'POST':
        form = forms.CreateArticle(request.POST, request.FILES)
        if form.is_valid():
            instance = form.save(commit=False)
            instance.author = request.user
            instance.save()
            return redirect('articles:list')
    else:
        form = forms.CreateArticle()
    return render(request, 'articles/article_create.html', { 'form': form })

Answer 1

保存表单后，必须调用form.save_m2m()。你的观点一定是这样的：

def article_create(request):
    if request.method == 'POST':
        form = forms.CreateArticle(request.POST, request.FILES)
        if form.is_valid():
            instance = form.save(commit=False)
            instance.author = request.user
            instance.save()
            form.save_m2m()
            return redirect('articles:list')
    else:
        form = forms.CreateArticle()
    return render(request, 'articles/article_create.html', { 'form': form })