django 编辑表单不保留值

Question

我为add 和edit 表单创建了一个简单的Django 表单。 我的问题出在我使用 ModelChoiceField 的人员领域。

在编辑表单中，除了字段ModelChoiceField 之外，所有值都解析正确。 在编辑表单中，该字段为空且不保留值，知道为什么吗？？

def edit_work(request, pk):
    instance = get_object_or_404(work, id=pk)
    form = workForm(request.POST or None,instance=instance)
    if form.is_valid():
        note = form.save(commit=False)
        note.save()
        return HttpResponseRedirect('/work/success/')
    return render(request,'edit_work.html', {'form': form})


 def add_work(request):
     if request.method == "POST":
         form = workForm(request.POST)
         if form.is_valid():
             note = form.save(commit=False)
             note.save()
             return render(request, "succes/erga_success.html")
     else:
         form = workForm()
     return render(request, 'add_work.html',{'form':form})

forms.py

class workForm(forms.ModelForm):
    peaople=forms.ModelChoiceField(queryset=User.objects.all(),required=False, error_messages={
            'invalid': _("---")})
    class Meta:
        model = work
        fields = (__all__")

html页面：

     <form  enctype="multipart/form-data" method="POST" action="">{% csrf_token %}
     {{form.peaople}}
     .........
     <input type="submit" value="create">
     </form>

Answer 1

该值没有被保留，因为您没有将它保存在任何地方，也没有分配它。

1. 将值保存在某处。

# views.py

# in both view functions
if form.is_valid():
    note = form.save(commit=False)
    note.save()
    somemodel.people = form.cleaned_data.get("people")
    somemodel.save()

1. 用保存的值初始化表单

def edit_work(request, pk):
    instance = get_object_or_404(work, id=pk)
    form = workForm(request.POST or None,instance=instance, initial={'people': somemodel.people})
    if form.is_valid():
        note = form.save(commit=False)
        note.save()
        somemodel.people = form.cleaned_data.get("people")
        somemodel.save()
        return HttpResponseRedirect('/work/success/')
    return render(request,'edit_work.html', {'form': form})

Answer 2

为什么要手动指定peaople 字段？也许这些数据没有保存在 WorkModel.peaople 字段下，而是手动保存在其他地方？考虑到 ModelChoiceField 是单个值，那么该字段很可能是 ForeignKey 并且命名不同（不是peaople）：如果 ModelForm 的自定义字段与模型上的同名字段不匹配，则默认不填充。

可能的解决方案：

• 如果模型字段名称与模型字段名称不同，则在初始化表单时应传递initial={'peaople': instance.some_human_fk_field} 参数。
• 如果您只需要将一些现有模型字段（例如some_human_fk_field）的widget/label/error_message等更改为ModelChoiceField, 'people', {'invalid': _("---")}，那么您完全可以don't need to define custom field：

class workForm(forms.ModelForm): 
    class Meta:
        model = work
        fields = ("__all__")
        labels = {
            'some_human_fk_field': _('People'),
        }
        error_messages = {
            'some_human_fk_field': {
                'invalid': _("---"),
            },
        }
        field_classes = {
            'some_human_fk_field': forms.ModelChoiceField,
        }

    def __init__(self, *args, **kwargs):
        super(workForm, self).__init__(*args, **kwargs)

        self.fields['some_human_fk_field'].queryset = User.objects.all()
        # Or you can dynamically determine queryset, for example you want to accout 'Work.owner.company' field: 
        # limiting_factor = None
        # if self.instance.pk:
        #     limiting_factor = self.instance.owner.company
        # elif self.data:
        #     _owner_pk = self.data.get('owner')
        #     limiting_factor = Company.objects.get(owners_set__pk=_owner_pk)
        # elif self.initial and self.initial.get('owner'):
        #     limiting_factor = self.initial['owner'].company

        # if limiting_factor:
        #     self.fields['some_human_fk_field'].queryset = build_qs_from_limiting_factor(
        #         User.objects.all(),
        #         company=limiting_factor
        #     )
        # else:
        #     self.fields['some_human_fk_field'].queryset = User.objects.all()

• 如果 work 模型上的 peaople 字段不是 FK（例如 TextField），那么您需要在表单初始化后“手动设置”field.initial：

class workForm(forms.ModelForm): 
    ...
    def __init__(self, *args, **kwargs):
        super(workForm, self).__init__(*args, **kwargs)
        if self.instance.pk and self.instance.peaople:
            self.fields['peaople'].initial = User.objects.filter(pk=self.instance.peaople)  # or `username=self.instance.peaople` depending on what you are really saving there