修改

Question

我有会员模型和组模型，其中包含来自会员的外键

class Member(models.Model):
    member_name = models.CharField(max_length=100)
    member_dob = models.DateField()

class Group(models.Model):
    group_name = models.CharField(max_length=100)
    group_owner = models.ForeignKey(Member, related_name='owner')
    group_members = models.ManyToManyField(Member, related_name='members')

我创建了另一个模型，Activity将引用Group和Member

class Activity(models.Model):
    group_id = models.ForeignKey(Group)
    topic = models.CharField(max_length=100)
    start_by = models.ForeignKey(Member, related_name='started')
    participants = models.ManyToManyField(Member, related_name='participants')

现在我已经为Acivity创建了一个ModelForm

class ActivityForm(ModelForm):
    class Meta:
        model = Activity

如果我在模板中使用了ActivityForm的对象，则所有用户都将加载到参与者的“选择”输入中。我希望仅显示属于选择选项中显示的组（具有id = self.group_id）的成员。

有人可以帮我编写一个查询集，我可以将其包含在ActivityForm的 init 函数中吗？

Answer 1

Member不应该Group拥有外键吗？您希望组中的许多成员不是很多，只有一个成员的组吗？

class Member(models.Model):
    name = models.CharField(max_length=100)
    dob = models.DateField()
    group = modes.ForeignKey('Group', related_name='members')

class Group(models.Model):
    name = models.CharField(max_length=100)
    owner = models.ForeignKey('Member', related_name='owned_groups')

class Activity(models.Model):
    group = models.ForeignKey('Group', related_name='activities')
    topic = models.CharField(max_length=100)
    start_by = models.ForeignKey('Member', related_name='started_activities')
    participants = models.ManyToManyField('Member', related_name='participating_activities')

然后你可以这样做：

class ActivityForm(ModelForm):
    def __init__(self, *args, **kwargs):
        super(ActivityForm, self).__init__(*args, **kwargs)
        if 'initial' in kwargs:
            self.fields['participants'].queryset = Member.objects.filter(group=initial.group)
    class Meta:
        model = Activity

修改

如果更改为使用ManyToManyField，我建议您修改字段名称和相关名称。在开发过程的早期进行更改会更容易，而不是在遇到无法修复的其他问题时。如果它更容易理解，只需这样思考：相关名称将在ForeignKey或ManyToManyField指向的模型上可访问，并包含queryset 0或更多条目。

所以，如果你有......

class Member(models.Model):
    name = models.CharField(max_length=100)
    dob = models.DateField()

class Group(models.Model):
    name = models.CharField(max_length=100)
    owner = models.ForeignKey('Member', related_name='owned_groups')
    members = models.ManyToManyField('Member', related_name='groups')

class Activity(models.Model):
    group = models.ForeignKey(Group)
    topic = models.CharField(max_length=100)
    start_by = models.ForeignKey('Member', related_name='started_activities')
    participants = models.ManyToManyField('Member', related_name='activities')

然后你可以做像...这样的事情。

g1 = Group.objects.create(name='Group 1', ...)
g2 = Group.objects.create(name='Group 2', ...)

member = Member.objects.get(name='John')
member.groups.all() # Get all the groups for the member
member.groups.add(g1, g2) # Add the member to 2 groups
member.activities.all() # Get all activities the member is a participant in
member.started_activities.all() # Get all activities started by the user

你的表格......

class ActivityForm(ModelForm):
    ...
    def __init__(self, *args, **kwargs):
        super(ActivityForm, self).__init__(*args, **kwargs)
        if 'initial' in kwargs:
            self.fields['participants'].queryset = initial.group.members.all()

    class Meta: 
        model = Activity

我认为这样可行，但如果没有：

class ActivityForm(ModelForm):
    ...
    def __init__(self, *args, **kwargs):
        super(ActivityForm, self).__init__(*args, **kwargs)
        if 'initial' in kwargs:
            self.fields['participants'].queryset = Member.objects.filter(group__id=initial.group.id)

    class Meta: 
        model = Activity

Answer 2

您的ActivityForm类需要有一个属性：

class ActivityForm(ModelForm):
    participants = forms.ModelMultipleChoiceField(queryset=Member.objects.filter(members__id==self.instance.group_id))

你的__init__函数应如下所示：

def __init__(self, *args, **kwargs):
    # call parent
    super(ActivityForm, self).__init__(*args, **kwargs)
    # fill initial values
    self.fields['participants'].initial = [c.pk for c in Member.objects.filter(members__id=self.instance.group_id, participants__in=self.instance)

1）您应该在组中重命名“related_name”。相关名称表示如何从其他类中获知该字段，例如。来自会员班

2）我认为你的上下文中的“group_members”应该是ManyToManyField。您的班级组现在允许您只将一个人存储到一个组中。

命名时可能会出现一些错误，因为您的相关名称非常混乱。

具有多个模型依赖关系的Django ModelForm字段过滤

2 个答案:

修改