如何正确使用 Django Forms

首先你要创建自己的Form类，继承于django的Form，
然后创建form中的字段，例子如下：

from django import forms
class AuthenticationForm(forms.Form):
"""
Base class for authenticating users. Extend this to get a form that accepts
username/password logins.
"""
username = forms.CharField(label=_("Username"), max_length=254)
password = forms.CharField(label=_("Password"), widget=forms.PasswordInput)

error_messages = {
'invalid_login': _("Please enter a correct username and password. "
"Note that both fields may be case-sensitive."),
'no_cookies': _("Your Web browser doesn't appear to have cookies "
"enabled. Cookies are required for logging in."),
'inactive': _("This account is inactive."),
}

1. Django Forms的强大之处

有些django项目并不直接呈现HTML, 二是以API框架的形式存在,
但你可能没有想到, 在这些API形式的django项目中也用到了django forms. django forms不仅仅是用来呈现HTML的,
他们最强的地方应该是他们的验证能力. 下面我们就介绍几种和Django forms结合使用的模式:

2. 模式一: ModelForm和默认验证

最简单的使用模式便是ModelForm和model中定义的默认验证方式的组合:

# myapp/views.py
from django.views.generic import CreateView, UpdateView

from braces.views import LoginRequiredMixin

from .models import Article

class ArticleCreateView(LoginRequiredMixin, CreateView):
model = Article
fields = ('title', 'slug', 'review_num')

class ArticleUpdateView(LoginRequiredMixin, UpdateView):
model = Article
fields = ('title', 'slug', 'review_num')
正如以上代码中看到的一样:

ArticleCreateView和ArticleUpdateView中设置model为Article
两个view都基于Article model自动生成了ModelForm
这些ModelForm的验证, 是基于Article model中定义的field转换而来的
3. 模式二, 在ModelForm中修改验证