限制形式的一個字段根據另一場

Question

的價值，我有三個型號那樣：

class SchoolClass(models.Model): 
    school = models.ForeignKey(School) 
    class_name = models.CharField(max_length=5) 

class School(models.Model): 
    name = models.CharField(max_length=100) 
    address = models.TextField(blank=True) 

class Student(models.Model): 
    school = models.OneToOneField(School, null=True) 
    class_id = models.ForeignKey(SchoolClass) 
    user = models.OneToOneField(User, on_delete=models.CASCADE) 

創建Django表單的學生，有沒有什麼辦法來設置表格只顯示這是在類我選擇的學校？

Answer 1

我認爲你想要做的是覆蓋你的窗體的__init__方法，這樣你就可以使用查詢來過濾掉你不需要的類。此查詢需要知道當前活躍的學生是誰，因此您必須將學生作爲關鍵字參數傳入。

事情是這樣的：

class NameOfForm(forms.Form)): 
    def __init__(self, *args, **kwargs): 
     current_student = kwargs.pop('student', None) 
     super(NameOfForm, self).__init__(*args, **kwargs) 
     classes_in_school = SchoolClass.objects.filter(school=current_student.school) 
     self.fields['name_of_field'] = ModelChoiceField(queryset = classes_in_school, 
                 required = True, 
                 label = "Choose a class") 

然後在你看來，當你創建表單，記得在當前的學生傳遞一個額外的參數。類似這樣的：

form = NameOfForm(request.POST or None, student=request.student)