django - 未显示表单实例

Question

View .py

@login_required
@user_passes_test(lambda u: u.is_superuser)
def date_format(request):
    save_msg = ''
    user = request.user
    try:
        settings = Settings.objects.get(user=user.id)
        settingsForm = SettingsForm(instance=settings)
    except:
        settings = None
        settingsForm = SettingsForm(initial={'date_format':0, 'time_format':0})
    if request.method == 'POST':
        settingsForm = SettingsForm(request.POST, instance=settings)
        if settingsForm.is_valid():
            settings = settingsForm.save(commit=False)
            settings.user = user
            settings.save()
            save_msg = 'Date format has been updated.'
    return render(request,'setting/date_format.html',
                           {
                            'about_menu': True,
                            'date_tab':True,
                            'SettingsForm':settingsForm,
                            'save_msg': save_msg,
                           })

模型.py

class Settings(models.Model):  
    user = models.ForeignKey(User, null=True)
    date_format = models.BooleanField('Date format', default=False)
    time_format = models.BooleanField('Time format', default=False)
    is_contactlist_active = models.BooleanField('Contacts', default=True)

对于初始值，显示默认格式。但是，如果我将该值保存到数据库，则值正在保存，但未显示所选格式(表单实例)。

Answer 1

老实说，您的代码很难遵循 - 也很难测试。首先用空函数拆分它:

def date_format(request):
    settings = _retrieve_user_settings() # see below
    form = _prepare_settings_form(settings) # see below

    if request.method == 'POST':
        form = _prepare_settings_form(settings, request.POST)
        if form.is_valid():
            _save_settings(form) # see below
            save_msg = 'Date format has been updated.'

     return render(request,'setting/date_format.html',
                           {
                            ...
                           }
      )


def _retrieve_user_settings()
    """
    get the logged-in user settings or None if the user is logged off or doesn't have any settings
    """
    pass

def _prepare_settings_form(settingsInstance=None, data=None)
    """
    prepare the form with the settings provided
    use default values if the settings are empty (to pre-fill the form)
    """
    pass

def _save_settings(form) # this one is even better out of the view
    # throw exception if the form wasn't validated
    # retrieve the user for the new settings
    # save the settings (attached to the user)
    pass

在着手实现这 3 个新的小功能的代码之前，编写它们的单元测试，您一定会以一个很好的工作代码结束。如果您认为这太费力，请查看此 StackOverflow 线程的大小以及您一直在进行的手动测试的数量；)

这只是一个示例，您可以以不同的方式拆分代码 - 但您应该真正避免在 try 语句中使用长 View 和长代码...