newforms 太好用了

建一个项目 newformstutorials ，建一个 app blog ，在 blog 的 models 中定义个：

class Article(models.Model):
    title = models.CharField(u'标题', maxlength=255)
    author = models.CharField(u'作者', maxlength=20)
    hits = models.IntegerField(u'点击数', default=0, editable=False)
    content = models.TextField(u'内容')

配置好数据库，把 newformstutorials.blog 加到 INSTALLED_APPS，manage.py syncdb，然后 manage.py shell ，然后：

In [1]: import django.newforms as forms

In [2]: from newformstutorials.blog.models import Article

In [3]: ArticleForm = forms.form_for_model(Article)

In [4]: form = ArticleForm()

In [5]: print unicode(form)
<tr><th><label for="id_title">标题:</label></th><td><input id="id_title" type="t
ext" name="title" maxlength="255" /></td></tr>
<tr><th><label for="id_author">作者:</label></th><td><input id="id_author" type=
"text" name="author" maxlength="20" /></td></tr>
<tr><th><label for="id_content">内容:</label></th><td><textarea id="id_content"
rows="10" cols="40" name="content"></textarea></td></tr>

In [6]: print form.as_ul()
<li><label for="id_title">标题:</label> <input id="id_title" type="text" name="t
itle" maxlength="255" /></li>
<li><label for="id_author">作者:</label> <input id="id_author" type="text" name=
"author" maxlength="20" /></li>
<li><label for="id_content">内容:</label> <textarea id="id_content" rows="10" co
ls="40" name="content"></textarea></li>

一个空白的 form 就这样出来了，这就是个添加文章的表单，让我们用这个表单来加点数据吧：

In [7]: form = ArticleForm({'title':'some title','author':'huangyi'})

In [8]: form.is_valid()
Out[8]: False

In [9]: form.errors
Out[9]: {'content': [u'This field is required.']}

In [10]: form = ArticleForm({'title':'some title','author':'huangyi', 'content':
'some contents...'})

In [11]: form.is_valid()
Out[11]: True

In [12]: article = form.save(commit=True)

OK，数据就这样保存了，我们再来试试数据更新的页面吧：

In [13]: ChangeForm = forms.form_for_instance(article)

In [14]: form = ChangeForm()

In [15]: print unicode(form)
<tr><th><label for="id_title">标题:</label></th><td><input id="id_title" type="t
ext" name="title" value="some title" maxlength="255" /></td></tr>
<tr><th><label for="id_author">作者:</label></th><td><input id="id_author" type=
"text" name="author" value="huangyi" maxlength="20" /></td></tr>
<tr><th><label for="id_content">内容:</label></th><td><textarea id="id_content"
rows="10" cols="40" name="content">some contents...</textarea></td></tr>

In [16]: form = ChangeForm({'title':'another title', 'author':'huangyi', 'conten
t':'other contents...'})
In [17]: form.is_valid()
Out[17]: True

In [18]: form.save()
Out[18]: <Article: Article object>

In [19]: article = Article.objects.get(id=article.id)

In [20]: article.title
Out[20]: 'another title'