我正在尝试为网站创建一个简单的页面版本控制系统。我希望能够将一个页面传递到一个表单中，该表单指向与该页面相关的所有版本，并让表单下拉列表包含该页面的所有版本，并使初始页面版本成为理想版本在 View 中初始化。到目前为止，表单将填写页面的所有版本，但不会选择理想的版本作为初始项。
如果在 View 中初始化表单时字段被填充，我如何设置表单中字段的初始项？
研究:
我试过以下问题的答案，但都没有解决方案:
- Setting initial value of Django ModelChoiceField
- Django: How to set initial values for a field in an inline model formset?
- Setting initial value of Django ModelChoiceField
示例代码:
模型.py
from django.db import models
from autoslug import AutoSlugField
from django_enumfield import enum
from ..users.models import User
def write_page(name, submitter, content=''):
page = Page.objects.get_or_create(name=name)[0]
page_version = PageVersion.create(page, submitter, content)
return page_version
class Status(enum.Enum):
DISABLED = 0
ACTIVE = 1
class Page(models.Model):
name = models.CharField(max_length=100)
slug = AutoSlugField(populate_from='name', unique=True)
status = enum.EnumField(Status, default=Status.ACTIVE)
current_version = models.IntegerField(default=0)
def __unicode__(self):
name_str = "(name='{}', slug='{}')"
return name_str.format(self.name, self.slug)
@property
def versions(self):
status = ("status = {}".format(Status.ACTIVE),)
order_by = ("-version",)
return self.pageversion_set.extra(where=status, order_by=order_by)
@property
def all_versions(self):
order_by = ("-version",)
return self.pageversion_set.extra(order_by=order_by)
@property
def ideal(self):
try:
return PageVersion.objects.get(id=self.current_version)
except self.DoesNotExist:
return None
@property
def version(self):
if self.ideal:
return self.ideal.version
return 0
@property
def content(self):
if self.ideal:
return self.ideal.content
return ''
@property
def submitter(self):
if self.ideal:
return self.ideal.submitter
return None
@classmethod
def create(cls, name):
page_object = cls.objects.create(name=name)
return page_object
class PageVersion(models.Model):
parent = models.ForeignKey(Page)
version = models.IntegerField(default=0)
content = models.TextField()
date = models.DateTimeField(auto_now_add=True)
status = enum.EnumField(Status, default=Status.ACTIVE)
submitter = models.ForeignKey(User)
def __unicode__(self):
name_str = "(name='{}', slug='{}', version={})"
return name_str.format(self.name, self.slug, self.version)
@property
def name(self):
return self.parent.name
@property
def slug(self):
return self.parent.slug
@classmethod
def create(cls, page, submitter, content='', make_current=True):
if page.all_versions:
current_max_version = max([i.version for i in page.all_versions])
else:
current_max_version = 0
page_version_object = cls(parent=page, submitter=submitter, content=content)
page_version_object.version = current_max_version + 1
page_version_object.save()
if make_current:
page.current_version = page_version_object.id
page.save()
return page_version_object
forms.py
from django import forms
from .models import PageVersion
class PageVersionForm(forms.Form):
version = forms.ModelChoiceField(queryset=None)
def __init__(self, *args, **kwargs):
page = kwargs.pop("page")
super(PageVersionForm, self).__init__(*args, **kwargs)
self.fields["version"].queryset = page.versions
views.py
from django.shortcuts import get_object_or_404, render
from django.http import HttpResponseRedirect, HttpResponseForbidden
from django.core.urlresolvers import reverse
from .models import Page, write_page
from .forms import PageForm, PageVersionForm
from ..helpers import get_pages
def update_page(request, slug):
if not request.user.has_perm("can_edit_page"):
return HttpResponseForbidden()
page = get_object_or_404(Page, slug=slug)
if request.method == "POST":
form = PageForm(request.POST)
if form.is_valid():
content = form.cleaned_data["content"]
user = request.user
write_page(name=page.name, submitter=user, content=content)
kwargs = {}
kwargs["slug"] = slug
return HttpResponseRedirect(reverse("pages:detail", kwargs=kwargs))
else:
data = {}
data["content"] = page.content
form = PageForm(data)
context = {}
page_version_form = PageVersionForm(page=page)
context["form"] = form
context["page_version_form"] = page_version_form
context["page"] = page
context["user"] = request.user
context.update(get_pages())
return render(request, "pages/page_update.html", context)
请您参考如下方法:
您需要重置 choices 属性，因为一旦设置了查询集，它就会缓存在字段上，并且即使您更新 queryset 属性也不会重新生效。
def __init__(self, *args, **kwargs):
...
self.fields['version'].queryset = page.versions
self.fields['version'].widget.choices = self.fields['version'].choices
你能检查一下你的 Django 版本中的 ModelChoiceField 是否有一个名为 _set_queryset 的 setter 方法吗？ ？它似乎在 github 中已修复。
