django - 如何限制表单集中的字段选择？

Question

我在限制表单集中的 optional 时遇到问题。我有以下模型:员工、部门、项目、项目类型、成员资格和角色。员工可以在表单集中添加/删除他们在给定部门项目中扮演的角色，表单应将可选项目限制为仅属于员工所属部门的项目。

型号:

class Department(models.Model):
    name = models.CharField(max_length=20)
    def __unicode__(self):
    return self.name

class Employee(models.Model):
    fname = models.CharField(max_length=15)
    department = models.ForeignKey(Department)
    def __unicode__(self):
        return self.fname

class Projecttype(models.Model):
    name = models.CharField(max_length=20)
    def __unicode__(self):
        return self.name

class Project(models.Model):
    projecttype = models.ForeignKey(Projecttype)
    department = models.ForeignKey(Department)
    members = models.ManyToManyField(Employee, through='Membership')
    def __unicode__(self):
       return "%s > %s" % (self.department, self.projecttype)

class Role(models.Model):
    name = models.CharField(max_length=20)
    def __unicode__(self):
       return self.name

class Membership(models.Model):
    project = models.ForeignKey(Project, null=True)
    department = models.ForeignKey(Department)
    employee = models.ForeignKey(Employee)
    role = models.ManyToManyField(Role, blank=True, null=True)
    class Meta:
        unique_together = (("project", "employee",),)

查看:

def employee_edit(request, employee_id):
    i = get_object_or_404(Employee, pk=employee_id)
    MembershipFormSet = modelformset_factory(Membership, exclude=('department', 'employee'),)
    f = MembershipFormSet(queryset=Membership.objects.filter(employee=i),)
    return render_to_response('gcs/edit.html', {'item': i, 'formset': f, }, context_instance=RequestContext(request))

现在，欧盟可以为任何部门的项目选择一个角色。它的作用是这样的:

项目选项:

Projects.objects.all()

我想用这样的方式限制项目:LIMIT PROJECT CHOCIES TO:

Projects.objects.filter(department=i.department)

Answer 1

这个Stack Overflow question是相当相似的。我喜欢 Matthew 的答案的方法，在该方法中，您可以在可以通过闭包访问员工的函数中动态构建表单。就您而言，您想要类似的东西:

from django.http import HttpResponseRedirect

def make_membership_form(employee):
    """
    Returns a Membership form for the given employee, 
    restricting the Project choices to those in the 
    employee's department. 
    """
    class MembershipForm(forms.ModelForm):
        project = forms.ModelChoiceField(queryset=Projects.objects.filter(department=employee.department))
        class Meta:
            model = Membership
            excludes = ('department', 'employee',)
    return MembershipForm

def employee_edit(request, employee_id):
    employee = get_object_or_404(Employee, pk=employee_id)
    # generate a membership form for the given employee
    MembershipForm = make_membership_form(employee)
    MembershipFormSet = modelformset_factory(Membership, form=MembershipForm)

    if request.method == "POST":
        formset = MembershipFormSet(request.POST, queryset=Membership.objects.filter(employee=employee))
        if formset.is_valid():
            instances = formset.save(commit=False)
                for member in instances:
                    member.employee = employee
                    member.department = employee.department
                    member.save()
            formset.save_m2m()
            # redirect after successful update
            return HttpResponseRedirect("")
    else:
        formset = MembershipFormSet(queryset=Membership.objects.filter(employee=employee),)
    return render_to_response('testdb/edit.html', {'item': employee, 'formset': formset, }, context_instance=RequestContext(request))