class A:
  min_v = 1
  max_v = 15
  number1 = IntegerField(min_value=min_v, max_value=max_v)

class B(A):
   number2 = IntegerField(min_value=A.min_v, max_value=A.max_v)

class C(B):
  min_v = 2
  max_v = 20

How to make both number1 and number2 to be in range from 2 to 20 in class C?

I'm thinking about two ways:

1. In __init__ redeclare self.fields['number1'] like IntegerField(min_value=self.min_v)
2. Set self.fields['number1'].min_value=self.min_v in __init__ and override setattr() to add validator.

What is the best and the cleanest way?

CodePudding user response：

It might be better to add these bounds as validators to the the bounds in the __init__ method of class A and class B. This will make these transparent to C and furthermore C can for example define another IntegerField for that name and thus specify a different widget for that:

from django.core import validators

class A:
    number1 = IntegerField()
    
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        number1 = self.fields['number1']
        number1.validators.append(validators.MinValueValidator(self.min_v))
        number1.validators.append(validators.MaxValueValidator(self.max_v))
        number1.widget.attrs['min'] = number1.min_value = self.min_v
        number1.widget.attrs['max'] = number1.max_value = self.max_v

class B(A):
    number2 = IntegerField()
    
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        number2 = self.field['number2']
        number2.validators.append(validators.MinValueValidator(self.min_v))
        number2.validators.append(validators.MaxValueValidator(self.max_v))
        number2.widget.attrs['min'] = number2.min_value = self.min_v
        number1.widget.attrs['max'] = number2.max_value = self.max_v