Django表单创建新记录而不是更新

我正在我的应用程序中创建用户更新表单。但每次提交表单时，它都会创建一条新记录，如果再次尝试提交，将返回完整性错误（重复用户名，两者均为空）

错误消息：django.db.utils.IntegrityError:唯一约束失败：auth_user.username

forms.py：

class UserChangeForm(forms.ModelForm):

    class Meta:
        model = User
        fields = ['email', 'first_name', 'last_name']

    def __init__(self, username, *args, **kwargs):
        super(UserChangeForm, self).__init__(*args, **kwargs)
        self.username = username

views.py：

def profile(request):

    user = request.user

    if request.method == 'POST':
        user_form = UserChangeForm(user, request.POST)

        if user_form.is_valid():
            user_form.save()
            messages.success(request, f'Your account has been updated!')

            return redirect('users:profile')

    else:
        email = request.user.email
        first_name = request.user.first_name
        last_name = request.user.last_name
        user_form = UserChangeForm(user, initial={
            'email': email,
            'first_name': first_name,
            'last_name': last_name
        })

    context = {
        'user_form': user_form,
    }

    return render(request, 'users/profile.html', context)

---

您需要在if条件和else条件下将用户作为实例传递，如下所示

def profile(request):
    if request.method == 'POST':
        user_form = UserChangeForm(request.POST , instance = request.user)

        if user_form.is_valid():
            user_form.save()
            messages.success(request, f'Your account has been updated!')

            return redirect('users:profile')

    else:
        user_form = UserChangeForm(instance=request.user)

    context = {
        'user_form': user_form,
    }
    return render(request, 'users/profile.html', context)