使 ModelForm 与 Django 中的中间模型建立多对多关系的步骤是什么? [英] What are the steps to make a ModelForm work with a ManyToMany relationship with an intermediary model in Django?

问题描述

• 我有一个 Client 和 Groupe 模型.
• 一个客户可以属于多个组.
• 客户是团体的一部分，可以随时使用团体的免费租金，但只能使用一次.这就是中介模型 (ClientGroupe) 带来额外数据的地方.

• I have a Client and Groupe Model.
• A Client can be part of multiple groups.
• Clients that are part of a group can use its group's free rental rate at anytime but only once. That is where the intermediary model (ClientGroupe) comes in with that extra data.

现在，当我尝试保存 m2m 数据时，它只是死了，并说我应该使用 ClientGroupe 管理器...那么缺少什么?

For now, when I try to save the m2m data, it just dies and says I should use the ClientGroupe Manager...so what's missing?

class Groupe(models.Model):
    nom = models.CharField(max_length=1500, blank=True)

class Client(models.Model):
    nom = models.CharField(max_length=450, blank=True)
    prenom = models.CharField(max_length=450, blank=True)
    groupes = models.ManyToManyField(Groupe, null = True, blank = True, through='ClientGroupe')

class ClientGroupe(models.Model):
    client = models.ForeignKey(Client)
    groupe = models.ForeignKey(Groupe)
    dt = models.DateField(null=True, blank=True) # the date the client is using its group's free rental rate    

    class Meta:
        db_table = u'clients_groupes'

这是我的观点:

def modifier(request, id):
    client = Client.objects.get(id=id)    
    form = ClientForm(instance = client)

    dict = {
        "form": form
        , "instance" : client
    }

    if request.method == "POST":
        form = ClientForm(request.POST, instance = client)

        if form.is_valid():
            client_mod = form.save()

            id = client_mod.id
            return HttpResponseRedirect(
                "/client/%(id)s/?err=success" % {"id" : id}
            )
        else:
            return HttpResponseRedirect(
                "/client/%(id)s/?err=warning" % {"id" : id}
            )

    return render_to_response(
        "client/modifier.html"
        , dict
        , context_instance=RequestContext(request)
    )

编辑:

这里是 ClientForm 代码:​​

and here's the ClientForm code:

class ClientForm(ModelForm):
    class Meta:
        model = Client

编辑 #2:这是错误消息:

AttributeError at /client/445/

Cannot set values on a ManyToManyField which specifies an intermediary model. Use ClientGroupe's Manager instead.

Request Method:     POST
Request URL:    http://localhost/client/445/
Exception Type:     AttributeError
Exception Value:    Cannot set values on a ManyToManyField which specifies an intermediary model.  Use ClientGroupe's Manager instead.

Exception Location:     C:Python25libsite-packagesdjangodbmodelsfields
elated.py  in __set__, line 574
Python Executable:  C:xamppapacheinapache.exe
Python Version:     2.5.2

推荐答案

…
if form.is_valid():
    client_mod = form.save(commit=False)
    client_mod.save()
    for groupe in form.cleaned_data.get('groupes'):
        clientgroupe = ClientGroupe(client=client_mod, groupe=groupe)
        clientgroupe.save()
    …

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