在这种情况下，为什么UserChangeForm模型会创建一个对象而不是更新它？

Question

我现在使用UserChangeForm来更新用户表单，当我尝试通过请求post发送时，函数确实起作用，但不会更改用户对象，而是像create方法一样保存对象。 那么，在这个时刻，我怎么能改变表单对象呢

views.py

# Edit Your account
@login_required
def edit_profile(request, user_slug=None):
    template_name = 'account/edit_profile.html'
    if request.method == "POST":
        request_user = request.user.userprofile
        user_profile = UserProfile.objects.get(slug=user_slug)
        form = EditForm(request.POST)
        if form.is_valid():
            form.instance.slug = user_slug
            form.save()
            return redirect('account:view_profile', form.instance.slug)
        return render(request, template_name, {'form': form})
    else:
        form = EditForm()
        user_profile = UserProfile.objects.get(slug=user_slug)
        return render(request, template_name, {'form': form})

url.py

urlpatterns = [
    path('view-profile/<slug:user_slug>/', views.view_profile, name='view_profile'),
    # /account/edit-profile/
    path('edit-profile/<slug:user_slug>/', views.edit_profile, name='edit_profile'),
]

编辑表单.html

{% extends 'base.html' %}
{% block title %} Edit Profile {% endblock %}

{% block body %}

    <div class="edit-form">
        <div class="container">
            <div class="my-form">
                <form method="post">
                    {% csrf_token %}
                    {% for field in form %}
                    <div class="form-group">
                        <label for="exampleInputEmail1">{{ field.label_tag }}</label>
                        <p>{{ field }}</p>
                    </div>
                    {% endfor %}
                <button type="submit" class="btn btn-primary btn-lg">Change Password</button>
                </form>
            </div>
        </div>
    </div>

    {% include 'base_footer.html' %}

{% endblock %}

forms.py

# Edit your data except password
class EditForm(UserChangeForm):
    password = None

    class Meta:
        model = User
        fields = ('first_name', 'last_name', 'email')

    def edit(self, fields):
        user = super(EditForm, self).save(commit=False)

        if user.commit:
            user.save()
        return user

Answer 1

Every ModelForm also has a save() method. This method creates and saves a database object from the data bound to the form. A subclass of ModelForm can accept an existing model instance as the keyword argument instance; if this is supplied, save() will update that instance. If it’s not supplied, save() will create a new instance of the specified model

因此，您只需将实例传递给EditForm

# Edit Your account
@login_required
def edit_profile(request, user_slug=None):
    template_name = 'account/edit_profile.html'
    if request.method == "POST":
        request_user = request.user.userprofile
        user_profile = UserProfile.objects.get(slug=user_slug)
        # if instance is supplied, save will update instead of create
        form = EditForm(request.POST, request.FILES, instance=user_profile)
        print(form.errors) # check if any errors
        if form.is_valid():
            # form.instance.slug = user_slug
            form.save()
            return redirect('account:view_profile', form.instance.slug)
        return render(request, template_name, {'form': form})
    else:
        user_profile = UserProfile.objects.get(slug=user_slug)
        # prepopulate the form data with model instance
        form = EditForm(instance=user_profile)
        return render(request, template_name, {'form': form})

注意：如果您也上传图像，请记住也要传递request.FILES