Django---ModelForm详解
示例:
from django.db import models from django.forms import ModelForm TITLE_CHOICES = ( ('MR', 'Mr.'), ('MRS', 'Mrs.'), ('MS', 'Ms.'), ) class Author(models.Model): name = models.CharField(max_length=100) title = models.CharField(max_length=3, choices=TITLE_CHOICES) birth_date = models.DateField(blank=True, null=True) def __str__(self): # __unicode__ on Python 2 return self.name class Book(models.Model): name = models.CharField(max_length=100) authors = models.ManyToManyField(Author) class AuthorForm(ModelForm): class Meta: model = Author #绑定数据库表 fields = ['name', 'title', 'birth_date'] #显示的字段(‘__all__’) class BookForm(ModelForm): class Meta: model = Book fields = ['name', 'authors']
选择用到的字段:
fields = [] 或 ‘__all__’
exclude = [ ]
save()方法:
每个ModelForm还具有一个save() 方法。这个方法根据表单绑定的数据创建并保存数据库对象。
模型表单的子类可以用关键字参数instance 接收一个已经存在的模型实例;如果提供,save() 将更新这个实例。
>>> from myapp.models import Article >>> from myapp.forms import ArticleForm # Create a form instance from POST data. >>> f = ArticleForm(request.POST) # 创建新对象 >>> new_article = f.save() # Create a form to edit an existing Article, but use # POST data to populate the form. #更新该对象 >>> a = Article.objects.get(pk=1) >>> f = ArticleForm(request.POST, instance=a) >>> f.save()
重写(覆盖)默认的字段:
from django.forms import ModelForm, Textarea from myapp.models import Author class AuthorForm(ModelForm): class Meta: model = Author fields = ('name', 'title', 'birth_date') widgets = { 'name': Textarea(attrs={'cols': 80, 'rows': 20}), }
覆盖字段:
from django.forms import ModelForm from myapp.models import Article from django.forms import fields class ArticleForm(ModelForm): slug = fields.ChoiceField() class Meta: model = Article fields = ['pub_date', 'headline', 'content', 'reporter', 'slug']
提供初始值:
>>> article = Article.objects.get(pk=1) >>> article.headline 'My headline' >>> form = ArticleForm(initial={'headline': 'Initial headline'}, instance=article) >>> form['headline'].value() 'Initial headline'
class XXXModelForm(ModelForm)
a.
class
Meta:
model,
# 对应Model的
fields
=
None
,
# 字段
exclude
=
None
,
# 排除字段
labels
=
None
,
# 提示信息
help_texts
=
None
,
# 帮助提示信息
widgets
=
None
,
# 自定义插件
error_messages
=
None
,
# 自定义错误信息(整体错误信息from django.core.exceptions import NON_FIELD_ERRORS)
field_classes
=
None
# 自定义字段类 (也可以自定义字段)
localized_fields
=
(
'birth_date'
,)
# 本地化,如:根据不同时区显示数据
如:
数据库中
2016
-
12
-
27
04
:
10
:
57
setting中的配置
TIME_ZONE
=
'Asia/Shanghai'
USE_TZ
=
True
则显示:
2016
-
12
-
27
12
:
10
:
57
b. 验证执行过程
is_valid
-
> full_clean
-
> 钩子
-
> 整体错误
c. 字典字段验证
def
clean_字段名(
self
):
# 可以抛出异常
# from django.core.exceptions import ValidationError
return
"新值"
d. 用于验证
model_form_obj
=
XXOOModelForm()
model_form_obj.is_valid()
model_form_obj.errors.as_json()
model_form_obj.clean()
model_form_obj.cleaned_data
e. 用于创建
model_form_obj
=
XXOOModelForm(request.POST)
#### 页面显示,并提交 #####
# 默认保存多对多
obj
=
form.save(commit
=
True
)
# 不做任何操作,内部定义 save_m2m(用于保存多对多)
obj
=
form.save(commit
=
False
)
obj.save()
# 保存单表信息
obj.save_m2m()
# 保存关联多对多信息
f. 用于更新和初始化
obj
=
model.tb.objects.get(
id
=
1
)
model_form_obj
=
XXOOModelForm(request.POST,instance
=
obj)
...
PS: 单纯初始化
model_form_obj
=
XXOOModelForm(initial
=
{...})