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[英]How to count all ForeignKey models with exact field values in Django?
[英]How do I set a foreignkey field in Django models to return no values?
我有一個 Django 模型,如:
class hotel(models.Model):
name = models.CharField(max_length=60)
city = models.ForeignKey('city', on_delete=models.DO_NOTHING)
state = models.ForeignKey('state', on_delete=models.DO_NOTHING)
country = models.ForeignKey('country', on_delete=models.DO_NOTHING)
def __str__(self):
return self.name
class Meta:
verbose_name_plural = "hotels"
class city(models.Model):
name = models.CharField(max_length=60)
state = models.ForeignKey('state', on_delete=models.DO_NOTHING)
def __str__(self):
return self.name
class Meta:
verbose_name_plural = "cities"
class state(models.Model):
name = models.CharField(max_length=60)
country = models.ForeignKey('country', on_delete=models.DO_NOTHING)
def __str__(self):
return self.name
class Meta:
verbose_name_plural = "states"
class country(models.Model):
name = models.CharField(max_length=60)
code = models.CharField(max_length=160)
def __str__(self):
return self.name
class Meta:
verbose_name_plural = "countries"
而 ModelForm 像:
class Hotel(ModelForm):
class Meta:
model = hotel
fields = '__all__'
[編輯] 從 Hotel ModelForm 創建表單對象時,Django 會自動填充外鍵字段的值。 我想阻止它。
例如:
form = Hotel()
(Django 自動填充城市、州和國家/地區值)
我希望我的 Django 模板在下拉列表中返回所有國家/地區值,但不返回州和城市下拉列表(因此我希望州和城市下拉列表在 Django 模板中保持為空)。 我怎樣才能做到這一點?
PS - 這樣做的目的是首先加載國家/地區值,根據用戶選擇的國家/地區,我將相應地加載州和城市。
您可以以__init__
方法的形式覆蓋選項,也可以在定義字段后使用設置選項的小技巧
class Hotel(ModelForm):
class Meta:
model = hotel
fields = '__all__'
# Like this
state = forms.ModelChoiceField(state.objects.all())
state.choices = []
city = forms.ModelChoiceField(city.objects.all())
city.choices = []
# Or like this...
def __init__(self, data=None, *args, **kwargs):
super().__init__(data=data, *args, **kwargs)
if not data:
self.fields['state'].queryset = state.objects.none()
self.fields['city'].queryset = state.objects.none()
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