如何在 Django ModelForms 中加载实例

Question

我正在使用 Django 的用户模型。

如何获取 Django ModelForm 以在模板中预填充值？我知道我必须使用该表单的实例，但下面哪里出错了：

models.py:

class Site(models.Model):
   user = models.ForeignKey(User, )
   site_name = models.CharField(max_length=128, blank=False, null=False)

forms.py:

class SiteForm(forms.ModelForm):
      class Meta:
            model = Site
            fields = '__all__'

views.py:

def settings(request):

    site_profile = Site.objects.get(user=request.user)

    if request.method == "POST":
        form = SiteForm( instance=site_profile )
            if form.is_valid():
                form.save()

                return redirect('dashboard_home')

        else:
            form = SiteForm()

        return render(request, "dashboard/settings.html", {'form': form })

此代码 returns 页面没有错误，但是没有使用数据库中的值预填充表单字段。

我只能假设 instance 加载不正确？

Answer 1

def settings(request):
    site_profile = Site.objects.get(user=request.user)

    if request.method == "POST":
        form = SiteForm( instance=site_profile )
            if form.is_valid():
                form.save()

                return redirect('dashboard_home')

    else:
        form = SiteForm(instance = site_profile)

        return render(request, "dashboard/settings.html", {'form': form })

第 12 行的 else 块缩进了一个 much
您还必须在 else 块中设置实例参数

Answer 2

def settings(request):
    if request.method == "POST":
        form = SiteForm(request.POST, instance=request.user.site_profile)
        if form.is_valid():
            form.save()
            return redirect('dashboard_home')
    site_profile = Site.objects.get(user=request.user)
    form = SiteForm(instance=site_profile)
    return render(request, "dashboard/settings.html", {'form': form })

您的缩进已关闭，您从未将 site_profile 传递给表单以填充它。在 POST 请求的情况下，您不想将旧版本的 site_profile 传递给表单。我假设您需要用户在模板中填写的新值。

Answer 3

根据我的经验，将默认行为假设为基于函数的视图中的 GET 请求将避免一些错误，并且您将摆脱那些 if-else 语句。如果您正在尝试编辑对象，您也需要在 GET 请求期间填充表单：

def settings(request):
    site_profile = Site.objects.get(user=request.user)
    form = SiteForm(instance=site_profile) # GET method
    if request.method == "POST":
        # Don't forget the request.POST !
        form = SiteForm(request.POST, instance=site_profile)
        if form.is_valid():
            form.save()
            return redirect('dashboard_home')
    return render(request, "dashboard/settings.html", {'form': form })

如何在 Django ModelForms 中加载实例

How to load an instance in Django ModelForms

python

django

django-models

django-forms

django-views