来自数据库的ModelChoiceField初始值

Question

I tried to find out how to set the initial value of a ModelChoiceField, I found many answers to this question but I don't really get them. I understand that I can set "initial" when calling the form in admin.py but then a model instance is mentioned and I am lost.

This is my models.py

class Articles(models.Model):
    headline = models.CharField('Rubrik', max_length=200)
    category = models.CharField('Kategori', max_length=200, blank=True)
    extract = models.TextField('Utdrag')
    image = ImageField('Bild', upload_to='articles', blank=True, default="")
    text = RichTextUploadingField('Text', blank=True, default="")
    added = models.DateTimeField('Publicerad', default=timezone.now,     blank=True)
    updated = models.DateTimeField('Uppdaterad',auto_now=True)
    frontpage = models.BooleanField('Visa på startsida', default=True)
    active = models.BooleanField('Aktiv', default=False)

    def save(self, *args, **kwargs):
        if self.added is None:
            self.added = timezone.now
        super(Articles, self).save(*args, **kwargs)

    def __unicode__(self):
        return '%s' % (self.headline)

    class Meta:
        verbose_name = "artikel"
        verbose_name_plural = "Artiklar"

This is my forms.py

class ArticleForm(forms.ModelForm):
category = forms.ModelChoiceField(queryset=Menu.objects.order_by('name').filter(category=True))

This is my admin.py

class ArticlesAdmin(admin.ModelAdmin):
form = ArticleForm
list_display = ('headline','category', 'extract', 'image', 'added', 'updated', 'frontpage', 'active')
admin.site.register(Articles, ArticlesAdmin)

When I edit the article in the admin section I want the stored value of the category to be the initial value for the ModelChoiceField. Do you get what I mean?

In admin.py there should be something like:

form = ArticleForm(initial = {'category':  instance.something})

*EDIT: I added ForeignKey as suggested

category = models.ForeignKey(Menu)

and admin.py looks like this:

class ArticlesAdmin(admin.ModelAdmin):
form = ArticleForm
list_display = ('headline','category', 'extract', 'image', 'added', 'updated', 'frontpage', 'active')

And now it's working as expected!

Answer 1

This code should work:

form = ArticleForm(initial = {'category':  pk})

pk is the stored value, pk = primary key