django：如何使用具有动态0-n可能性的ModelForm？

Question

Quetion

您好。我试图找出使用一个表单创建一个父对象然后创建0-n子对象的最佳方法。我假设ModelForms是我需要做的，但我很难理解如何构建模板和视图。有人愿意解释如何创建n个子对象吗？

研究

我已经阅读了其他几篇与此相关的文章和帖子：

• django model/modelForm - How to get dynamic choices in choiceField?
• https://stackoverflow.com/questions/5575560/how-do-i-create-a-drop-down-menu-in-django-using-a-modelform-with-dynamic-values
• http://collingrady.wordpress.com/2008/02/18/editing-multiple-objects-in-django-with-newforms/
• Overriding the save method in Django ModelForm

仅举几例。

详情

我有两个这样的模型：

// models.py

class DataItem(models.Model):
    name = models.CharField(max_length=255)
    date_created = models.DateTimeField(auto_now_add=True)
    date_last_updated = models.DateTimeField(auto_now_add=True)
    owner = models.ForeignKey(User, blank=False)

    def __unicode__(self):
        return self.name

class DataItemSet(models.Model):
    item = models.ForeignKey(DataItem, blank=False)
    type_ind = models.IntegerField()

我创建了两个ModelForms来对应：

// forms.py

class CreateDataItemForm(forms.ModelForm):

    class Meta:
        model = DataItem
        exclude = ('owner',)

    def save(self, user, commit=True):
        item = super(CreateDataItemForm,self).save(commit=False)
        item.owner = user
        if commit:
            item.save()
        return item


class CreateDataItemSetForm(forms.ModelForm):

    class Meta:
        model = DataItemSet
        exclude = ('item',)

    def save(self, parent, commit=True):
        set = super(CreateDataItemSetForm,self).save(commit=False)
        set.item = parent
        if commit:
            set.save()
        return set

在我看来，我正在尝试让一个表单提交由DataItem拥有的新DataItemSet和1-n DataItem的创建。以下是表单输出的示例：

模板：

<form action="." method="post">
    {% csrf_token %}
    <table>
        {{ create_form.as_table }}
    </table>
    <table>
        <tr>
            <th>What to track:</th>
            <td>
                <select>
                    <option value="1">Number</option>
                    <option value="2">Currency ($)</option>
                    <option value="3">Date</option>
                    <option value="4">Day</option>
                    <option value="5">Time</option>
                </select>
            </td>
            <td>

            </td>
        </tr>
        <tr>
            <th>What to track:</th>
            <td>
                <select>
                    <option value="1">Number</option>
                    <option value="2">Currency ($)</option>
                    <option value="3">Date</option>
                    <option value="4">Day</option>
                    <option value="5">Time</option>
                </select>
            </td>
            <td>
                <button type="button">+</button>
            </td>
        </tr>
    </table>
    <p>
        <button type="submit">Create</button>
    </p>
</form>

最后，观点：

// views.py

@login_required
@csrf_protect
def create_data_item(request):
    create_form = CreateDataItemForm()
    c = {'create_form':create_form}
    c.update(csrf(request))
    if request.method == 'POST':
        data = request.POST.copy()
        form = CreateDataItemForm(data, instance=DataItem())
        item_sets = [CreateDataItemSetForm(request.POST, prefix=str(x), instance=DataItemSet()) for x in range(0,9)]
        if form.is_valid():
            # create new data item
            new_item = form.save(request.user)
            #create new set of stuff to track
            for item_set in item_sets:
                new_item_set = item_set.save(new_item)
            # return to the add entry page
            return redirect('/add')
    else:
        return render_to_response('internal/create_data_item.html',c)

我遗漏了如何允许从form动态提取0-n DataItemSets。我无法用ModelForm搞清楚。

感谢您的帮助！

Answer 1

这是model formsets - 具体而言，inline formsets - 的用途。