python - Django View 类: name 'self' is not defined

Question

我正在研究 Django 框架。现在我正在为用户注册创建一个类，如下所示。我在第 6 行遇到错误。你能提供一些帮助吗？

1: class JoinForm(forms.Form):
2:    MONTH = {
3:        1:('Jan'), 2:('Feb'), 3:('March'), 4:('Apl'), 5:('May'), 6:('Jun'),
4:        7:('July'), 8:('Aug'), 9:('Sep'), 10:('Oct'), 11:('Nov'), 12:('Dec')
5:    }
6:    YEAR = self.makeYearChoice(self,1940)
7:    email = forms.EmailField(label='Email Address', max_length=50)
8:    name = forms.CharField(label='Real Name', max_length=20)
9:    birth = forms.DateField(label='Birth Date', widget=SelectDateWidget(years=YEAR, months=MONTH))
10:   loc = forms.CharField(label='Resident Location', max_length=40)
11:   passwd = forms.CharField(label='Password', max_length=16, widget=forms.PasswordInput)

12:   def makeYearChoice(self,startYear):
13:       YEARS = ();
14:       thisYear = datetime.now().year
15:       for year in range(startYear,thisYear):
16:           YEARS.append(year)
17:       return YEARS

Answer 1

这与Django无关；类定义的主体有自己的命名空间，并按编写的顺序运行，因此此时:

class JoinForm(forms.Form):
    ...
    YEAR = self.makeYearChoice(self,1940)  # here
    ...

不仅 self 未定义，makeYearChoice 也未定义!您可以通过以下两种方法之一修复此问题:

1. 将方法定义移至类属性设置之上，并直接调用

   class JoinForm(forms.Form):
       ...
       def makeYearChoice(self, startYear):  # define the method first
           ...
   
       YEAR = makeYearChoice(None,1940)  # don't have an instance, but who cares?
       ...
   

   一旦定义了类，就会留下多余的实例方法；或

2. 将其设为独立函数并在类中调用它:

   def makeYearChoice(startYear):
       ...
   
   class JoinForm(forms.Form):
       ...
       YEAR = makeYearChoice(1940)  # no fuss about self argument
       ...
   

我强烈支持后者。另外，您应该阅读the style guide ;方法和属性名称通常为 lowercase_with_underscores，并且逗号后应有空格。