Django raise forms.ValidationError 不起作用

我正在尝试向 django 模型表单添加一个验证器，这样如果选择了特定值，则应输入表单中的其他字段，如果未输入，则应给出验证错误

在下面的表单中，如果用户从 Activity_name 下拉列表中选择“项目支持活动”，则项目 ID 字段应为必填字段

姜戈形式

class ActivityTrackerModelForm(forms.ModelForm):
    date = forms.DateField(label='', widget=forms.DateInput(attrs={
                           "placeholder": "Select Date", 'id': 'datepicker', 'class': 'form-control w-100', 'autocomplete': 'off'}))
    activity_name = forms.ModelChoiceField(queryset=activity.objects.all().order_by(
        'activity_name'), label='', empty_label="Select Activity", widget=forms.Select(attrs={'class': 'form-control w-100'}))
    system_name = forms.ModelChoiceField(queryset=system.objects.all().order_by('system_name'), label='', empty_label="Select System", widget=forms.Select(attrs={
'class': 'form-control w-100'}))
    client_name = forms.ModelChoiceField(queryset=client.objects.all().order_by(
        'client_name'), label='',  empty_label="Select Client", widget=forms.Select(attrs={
'class': 'form-control w-100'}))
    hour_choice = [('', 'Choose Hours'), (0, 0), (1, 1), (2, 2),(3, 3), (4, 4), (5, 5), (6, 6), (7, 7), (8, 8)]
    hours = forms.ChoiceField(label='', choices=hour_choice, widget=forms.Select(
        attrs={'class': 'form-control w-100'}))
    min_choice = [('', 'Choose Mins'), (0, 0), (15, 15), (30, 30), (45, 45)]
    mins = forms.ChoiceField(label='', choices=min_choice, widget=forms.Select(attrs={'class': 'form-control w-100'}))
    no_of_records = forms.IntegerField(label='', required=False, widget=forms.NumberInput(
        attrs={"placeholder": "Enter no. of Records", 'class': 'form-control w-100', 'autocomplete': 'off'}))
    project_id = forms.CharField(label='', required=False, widget=forms.TextInput(
        attrs={"placeholder": "Project ID", 'class': 'form-control w-100'}))
    user_comments = forms.CharField(
        label='',
        required=False,
        widget=forms.Textarea(
            attrs={
                "placeholder": "Enter Your Comments Here...",
                'rows': 6,
                'class': 'form-control w-100',
                'autocomplete': 'off'
            }
        )
    )

    class Meta:
        model = activity_tracker
        fields = ['date', 'activity_name', 'system_name', 'client_name',
                  'hours', 'mins', 'no_of_records', 'project_id', 'user_comments']


    def clean(self):
        cleaned_data = super(ActivityTrackerModelForm, self).clean()
        activity = cleaned_data.get('activity_name')
        project_1 = cleaned_data.get('project_id')
        if re.search("^Project.*Activities$", str(activity)) or project_1 is None:
            print('pass') # prints to console this is working
            raise forms.ValidationError('Please Add in Project ID')#raise form error this is not working

View :

def MyTask(request):
    if request.method == 'POST':
        form = ActivityTrackerModelForm(request.POST or None)
        if form.is_valid():
            obj = form.save(commit=False)
            obj.user_name = request.user
            obj.approver = tascaty_user.objects.get(
                username=request.user).approver
            if request.user.is_team_lead:
                obj.status = activity_status.objects.get(pk=3)
            obj.save()
        return redirect('mytask')

    queryset1_PA = activity_tracker.objects.filter(
        user_name=request.user).filter(status__in=[1, 2, 4]).order_by('-id')
    queryset1_AP = activity_tracker.objects.filter(
        user_name=request.user).filter(status=3).order_by('-date')
    paginator_RA = Paginator(queryset1_AP, 10)
    paginator_PA = Paginator(queryset1_PA, 10)
    page = request.GET.get('page')

    context = {
        'title': 'TasCaty|My Task',
        'activity_form': ActivityTrackerModelForm(),
        'post_page_RA': paginator_RA.get_page(page),
        'post_page_PA': paginator_PA.get_page(page),
    }
    return render(request, "tascaty/mytask.html", context)

提高错误工作正常。但即使表单无效，您也总是重定向离开，因此永远不会显示错误。

仅当 is_valid 为 True 时才应重定向，否则应重新显示表单。这意味着将无效表单传递回上下文 - 因此您应该仅在方法不是 POST 时创建一个新表单。所以：

if request.method == 'POST':
    form = ActivityTrackerModelForm(request.POST or None)
    if form.is_valid():
        ...
        obj.save()
        return redirect('mytask')   # indented here
else:
    ActivityTrackerModelForm()      # added this block, note it's aligned with the first if

...

context = {
    ...
    'activity_form': form,         # pass the existing form here
    ...
}
return render(request, "tascaty/mytask.html", context)