如何使用一些計算從不同的ModelForm字段填充模型字段值？

Question

我想在我的ModelForm中有age字段，並用它來填充模型中的birth_year。
做這件事的慣用方法是什麼？我應該在我的表格或模型或元類中提供什麼方法​​？

Answer 1

from datetime import datetime 
import forms 
from myapp.models import MyModel 


class MyAgeForm(forms.ModelForm): 
    age = forms.IntegerField() 
    # define other custom fields here 

    class Meta: 
     model = MyModel 
     # probably define what fields from the model to include/exclude here 


    def save(self, *args, **kwargs): 
     self.instance.birth_year = datetime.now().year - self.cleaned_data['age'] 
     return super(MyAgeForm, self).save(*args, **kwargs)