Python 如何将数据从表单中的ManaToManyField获取到Django视图中？

型号.py

class Posts(models.Model):
   """model for CreatePost"""
   author = models.CharField(max_length=100, null=False, blank=False)

   blog_title = models.CharField(max_length=100, null=False, blank=False)

   sub_catagory = models.ManyToManyField('SubCatagory')

   post_cover_image = models.ImageField(upload_to='post_cover_images', null=False, blank=False)

   post_discription = HTMLField(max_length=5000, null=False, blank=False, help_text='Enter the detailed post in max. 5000 characters')

   date_published = models.DateField(null=False, blank=False)

class Catagory(models.Model):
   """model for Catagory"""
   name = models.CharField(max_length=150, help_text='Enter a ctagory for blogpost')

class SubCatagory(models.Model):
   """model for subcatagories"""
   catagory = models.ForeignKey('Catagory', on_delete=models.CASCADE)
   sub_catagory_name = models.CharField(max_length=150, help_text='Enter subcatagory')

class PostCreationForm(forms.ModelForm):
    class Meta:
        model = Posts
        fields = ('blog_title', 'sub_catagory', 'post_cover_image', 'post_discription')

@login_required
def createpost(request):
    if request.method=="POST":
        PostForm = PostCreationForm(request.POST, request.FILES)

        if PostForm.is_valid():

            postcont = Posts()

            if request.user.is_authenticated:
                postcont.blog_title = PostForm.cleaned_data['blog_title']
                postcont.post_cover_image = PostForm.cleaned_data['post_cover_image']
                postcont.post_discription = PostForm.cleaned_data['post_discription']
                postcont.author = request.user.username
                postcont.sub_catagory = PostForm.cleaned_data['sub_catagory']
                postcont.date_published = datetime.date.today()
                postcont.save()

                return HttpResponseRedirect(reverse('postcreationsuccessful'))
            else:
                return HttpResponseRedirect(reverse('createpost'))

    else:
        PostForm = PostCreationForm()

    return render(request, 'createpost.html', {'PostForm':PostForm})

forms.py

class Posts(models.Model):
   """model for CreatePost"""
   author = models.CharField(max_length=100, null=False, blank=False)

   blog_title = models.CharField(max_length=100, null=False, blank=False)

   sub_catagory = models.ManyToManyField('SubCatagory')

   post_cover_image = models.ImageField(upload_to='post_cover_images', null=False, blank=False)

   post_discription = HTMLField(max_length=5000, null=False, blank=False, help_text='Enter the detailed post in max. 5000 characters')

   date_published = models.DateField(null=False, blank=False)

class Catagory(models.Model):
   """model for Catagory"""
   name = models.CharField(max_length=150, help_text='Enter a ctagory for blogpost')

class SubCatagory(models.Model):
   """model for subcatagories"""
   catagory = models.ForeignKey('Catagory', on_delete=models.CASCADE)
   sub_catagory_name = models.CharField(max_length=150, help_text='Enter subcatagory')

class PostCreationForm(forms.ModelForm):
    class Meta:
        model = Posts
        fields = ('blog_title', 'sub_catagory', 'post_cover_image', 'post_discription')

@login_required
def createpost(request):
    if request.method=="POST":
        PostForm = PostCreationForm(request.POST, request.FILES)

        if PostForm.is_valid():

            postcont = Posts()

            if request.user.is_authenticated:
                postcont.blog_title = PostForm.cleaned_data['blog_title']
                postcont.post_cover_image = PostForm.cleaned_data['post_cover_image']
                postcont.post_discription = PostForm.cleaned_data['post_discription']
                postcont.author = request.user.username
                postcont.sub_catagory = PostForm.cleaned_data['sub_catagory']
                postcont.date_published = datetime.date.today()
                postcont.save()

                return HttpResponseRedirect(reverse('postcreationsuccessful'))
            else:
                return HttpResponseRedirect(reverse('createpost'))

    else:
        PostForm = PostCreationForm()

    return render(request, 'createpost.html', {'PostForm':PostForm})

视图.py

class Posts(models.Model):
   """model for CreatePost"""
   author = models.CharField(max_length=100, null=False, blank=False)

   blog_title = models.CharField(max_length=100, null=False, blank=False)

   sub_catagory = models.ManyToManyField('SubCatagory')

   post_cover_image = models.ImageField(upload_to='post_cover_images', null=False, blank=False)

   post_discription = HTMLField(max_length=5000, null=False, blank=False, help_text='Enter the detailed post in max. 5000 characters')

   date_published = models.DateField(null=False, blank=False)

class Catagory(models.Model):
   """model for Catagory"""
   name = models.CharField(max_length=150, help_text='Enter a ctagory for blogpost')

class SubCatagory(models.Model):
   """model for subcatagories"""
   catagory = models.ForeignKey('Catagory', on_delete=models.CASCADE)
   sub_catagory_name = models.CharField(max_length=150, help_text='Enter subcatagory')

class PostCreationForm(forms.ModelForm):
    class Meta:
        model = Posts
        fields = ('blog_title', 'sub_catagory', 'post_cover_image', 'post_discription')

@login_required
def createpost(request):
    if request.method=="POST":
        PostForm = PostCreationForm(request.POST, request.FILES)

        if PostForm.is_valid():

            postcont = Posts()

            if request.user.is_authenticated:
                postcont.blog_title = PostForm.cleaned_data['blog_title']
                postcont.post_cover_image = PostForm.cleaned_data['post_cover_image']
                postcont.post_discription = PostForm.cleaned_data['post_discription']
                postcont.author = request.user.username
                postcont.sub_catagory = PostForm.cleaned_data['sub_catagory']
                postcont.date_published = datetime.date.today()
                postcont.save()

                return HttpResponseRedirect(reverse('postcreationsuccessful'))
            else:
                return HttpResponseRedirect(reverse('createpost'))

    else:
        PostForm = PostCreationForm()

    return render(request, 'createpost.html', {'PostForm':PostForm})

模板

{% extends "base_generic.html" %}

{% block title %}<title>Create Post</title>{% endblock %}

{% block content %}
    <div class="container-fluid">
        <div class="row w-100">
            <div class="col-md-3">

            </div>
            <div class="col-md-6 shadow-sm p-3 mb-5 bg-white rounded">
                <form method="POST" enctype="multipart/form-data" action="{% url 'createpost' %}">{% csrf_token %}
                    <div class="row">
                        {% load bootstrap %}
                        <div class="col-md-12">
                            {{ PostForm.blog_title|bootstrap }}
                        </div>
                        <div class="col-md-12">
                            {{ PostForm.post_cover_image|bootstrap }}
                        </div>
                        <div class="col-md-12">
                            {{ PostForm.sub_catagory|bootstrap }}
                        </div>
                        <div class="col-md-12">
                            {{ PostForm.post_discription }}
                        </div>
                        <div class="col-md-12">
                            <input type="submit" value="Post">
                        </div>
                    </div>
                </form>
            </div>

            <div class="col-md-3">

            </div>
        </div>
    </div>
 {% endblock %}

{%extensed“base_generic.html”%}
{%block title%}创建帖子{%endblock%}
{%block content%}
{%csrf_令牌%}
{%load bootstrap%}
{{PostForm.blog_title | bootstrap}}
{{PostForm.post_cover_image|bootstrap}
{{PostForm.sub|catogory | bootstrap}}
{{PostForm.post_description}}
{%endblock%}

我的问题是，我在帖子和子标签中有很多关系。作为子标记，可以有许多帖子。我希望获得用户选择的类别，并希望使用views.py函数将它们保存在模型中

我想问我怎么能做到这一点。当我尝试这样做时：

postcont.sub_catagory=PostForm.cleaned_数据['sub_catagory']

我得到以下错误：

/posts/createpost处的类型错误/ 禁止直接分配到多对多集合的前端。改为使用sub_catagory.set（）

---

任何人都请帮忙

正如错误所说，问题在于这一行：

postcont.sub_catagory = PostForm.cleaned_data['sub_catagory']

sub_category

是一个

ManyToManyField

，因此不能直接将其设置为对象。您可以使用

postcont.sub\u category.set（PostForm.cleaned\u data['sub\u category']）

，但这仍然不是很优雅

您的视图实际上不必为对象修补所有字段。我们可以让表单完成以下工作：

@login_required
def createpost(request):
    if request.method=="POST":
        post_form = PostCreationForm(request.POST, request.FILES)

        if post_form.is_valid():
            post_form.instance.auther = request.user.username
            postcont.instance.date_published = datetime.date.today()
            post_form.save()
            return redirect('postcreationsuccessful')
    else:
        post_form = PostCreationForm()

    return render(request, 'createpost.html', {'PostForm': post_form})

@需要登录\u
def createpost（请求）：
如果request.method==“POST”：
post_form=PostCreationForm（request.post，request.FILES）
如果post\u表单有效（）：
post_form.instance.auther=request.user.username
postcont.instance.date_published=datetime.date.today（）
post_form.save（）
返回重定向（'postcreationsuccessful'）
其他：
post_form=后创建表单（）
返回呈现（请求'createpost.html'，{'PostForm'：post\u form}）

一些额外的评论：

if request.user.is\u authenticated无效，因为

@login\u required

装饰程序已经检查了这一点

如果

作者

是

用户

，最好在此处使用

外键（用户，…）

您可以使用

date\u published=models.DateField（auto\u add\u now=True，null=False）

作为

date\u published

字段，以确保“date\u published”自动设置为构建对象的日期

通过在表单无效的情况下不重定向，您实际上可以呈现带有错误的表单，这样用户就可以修复表单，然后重新提交；及

您可以使用

返回重定向（..）

，它是

反向（..）

的快捷方式，包装在

HttpResponseRedirect（..）

对象中

---

等等，你自己根据表单构造了一个实例？为什么？在

有效后，您可以使用
PostForm.save（）
，而且最好使用小写变量，因此
PostForm
。如果使用PostForm.save（）语句，我将无法将发布日期和用户名保存到模型中。您只需先构造一个对象，然后用
表单中的
instance=my\u object
传递它。此外，您可以将
date\u published
设置为
日期字段（auto\u add\u now=True）
，这样它会自动将日期设置为构建实例的日期。我尝试了。它对保存许多字段选择有用吗？