django - 值错误 : Cannot assign : must be an instance

Question

所以我是 Django 的新手，我正在尝试保存一个模型 Ovelse 的新实例，它有一个指向另一个模型 Okt 的外键。我有一个 View ，其中包含所有 Okt 实例的列表，该列表链接到连接到每个 Okt 的所有 Ovelse 实例。

模型.py

class Okt(models.Model):

def __str__(self):
    return '{}, uke {}, dag {}'.format(self.sykel_navn, self.sykel_uke, self.sykel_dag)


sykel_navn = models.CharField(max_length=8, default="Sykel 1")
sykel_dag = models.CharField(max_length=(1), choices=(SYKEL_DAGER))
sykel_uke = models.CharField(max_length=(1), choices=(SYKEL_UKER))
dato = models.DateTimeField('Dato på treningsøkt: ')
notater = models.CharField(max_length=400)


class Ovelse(models.Model):

okt = models.ForeignKey(Okt, on_delete=models.CASCADE)
ovelse_type = models.CharField(max_length=2, choices=MUSKELGRUPPE_CHOICES)
ovelse_navn = models.CharField(max_length=20)
vekt = models.IntegerField(default=0, name='kg')
sets = models.PositiveIntegerField(default=2)
reps = models.PositiveIntegerField(default=2)

def __str__(self):
    return self.ovelse_navn

View .py

class OvelseCreateView(generic.CreateView):
model = Ovelse
template_name = 'trening/add.html'
form_class = OvelseForm

def form_valid(self, form):
    form.instance.okt = self.kwargs.get('pk')
    return super(OvelseCreateView, self).form_valid(form)

表单.py

class OvelseForm(forms.ModelForm):

class Meta:
    model = Ovelse
    exclude = ['okt',]
    fields = ['ovelse_navn', 'ovelse_type', 'kg', 'sets', 'reps']

def __init__(self, *args, **kwargs):
    super(OvelseForm, self).__init__(*args, **kwargs)
    self.fields['ovelse_type'].label = "Muskler brukt"
    self.fields['ovelse_navn'].label = "Navn på øvelsen"
    self.fields['kg'].label = "Antall kilo"
    self.fields['sets'].label = "Antall set"
    self.fields['reps'].label = "Antall reps"

当我尝试提交表单时，收到错误消息:无法分配“1”:“Ovelse.okt”必须是“Okt”实例，而我希望创建该实例的新模型。

Answer 1

由于您正在“注入(inject)”主键本身，而不是 Okt 对象，因此您应该使用 .okt_id 而不是 .okt:

class OvelseCreateView(generic.CreateView):

    model = Ovelse
    template_name = 'trening/add.html'
    form_class = OvelseForm

    def form_valid(self, form):
        form.instance.<b>okt_id</b> = self.kwargs.get('pk')
        return super(OvelseCreateView, self).form_valid(form)

请注意，您可以在表单的 Meta 类中设置标签，为此无需覆盖 __init__ 文件:

class OvelseForm(forms.ModelForm):

    class Meta:
        model = Ovelse
        exclude = ['okt',]
        fields = ['ovelse_navn', 'ovelse_type', 'kg', 'sets', 'reps']
        <b>labels</b> = {
            'ovelse_type': 'Muskler brukt',
            'ovelse_navn': 'Navn på øvelsen',
            'kg': 'Antall kilo',
            'sets': 'Antall set',
            'reps': 'Antall reps'
        }