如何以编程方式获得 Django 模型字段的 max_length？

假设我有一个类似这样的 Django 类:

class Person(models.Model):
name = models.CharField(max_length=50)
# ...

如何以编程方式获取 name字段的 max_length值？

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小开

最佳答案

Person._meta.get_field('name').max_length will give you this value. ~~But having to use _meta suggests this is something you shouldn't do in normal usage.~~

Edit: as Carl pointed out, this naming is misleading and it does seem quite acceptable to use it: http://www.b-list.org/weblog/2007/nov/04/working-models/

小开

The question is regarding models, but for people trying to do the same for forms (that's how I ended up in this thread), I think this approach is quite simple and clear:
1. In a template:
\{\{form.name.field.max_length}}

2. In python code (e.g. in the view)
form.name.field.max_length