简介
Model + Form ==> ModelForm。model和form的结合体,所以有以下功能:
- 验证
- 数据库操作
Form回顾
models.py
class UserType(models.Model): caption = models.CharField(max_length=32) class UserInfo(models.Model): username = models.CharField(max_length=32) email = models.EmailField() user_type = models.ForeignKey(to=‘UserType‘,to_field=‘id‘)
forms.py
from django import forms from django.forms import fields class UserInfoForm(forms.Form): # username = models.CharField(max_length=32) <-- models username = fields.CharField(max_length=32) # email = models.EmailField() <-- models email = fields.EmailField() # user_type = models.ForeignKey(to=‘UserType‘,to_field=‘id‘) <-- models user_type = fields.ChoiceField( choices=models.UserType.objects.values_list(‘id‘,‘caption‘) ) # 下面的操作是让数据在网页上实时更新。 def __init__(self, *args, **kwargs): super(UserInfoForm,self).__init__(*args, **kwargs) self.fields[‘user_type‘].choices = models.UserType.objects.values_list(‘id‘,‘caption‘)
index.html
<body> <form action="/index/" method="POST" novalidate="novalidate"> % csrf_token % obj.as_p <input type="submit" value="提交"> </form> </body>
从上面的小例子能看出,models的字段和forms的字段大部分都是重复的,所以,django给我们提供了一种更为简洁的ModelFrom
ModelForm的用法
forms.py
class UserInfoModelForm(forms.ModelForm): class Meta: model = models.UserInfo # 与models建立了依赖关系 fields = "__all__"
views.py
def index(request): if request.method == "GET": obj = UserInfoModelForm() return render(request,"index.html",‘obj‘:obj) elif request.method == "POST": obj = UserInfoModelForm(request.POST) print(obj.is_valid()) # 这是方法,别忘记了加括号 print(obj.cleaned_data) print(obj.errors) return render(request,"index.html",‘obj‘:obj)
index.html
<body> <form action="/index/" method="POST" novalidate="novalidate"> % csrf_token % obj.as_p <input type="submit" value="提交"> </form> </body>
ModelForm常见参数
自定义字段名(html显示的字段)
如何定义http上定义的字段呢,自定义写成中文的?之前的用法是在Form里写上label。Model Form定义要用verbose_name
指定显示那些字段
class UserInfo(models.Model): username = models.CharField(max_length=32, verbose_name=‘用户‘) email = models.EmailField(verbose_name=‘邮箱‘) user_type = models.ForeignKey(to=‘UserType‘,to_field=‘id‘, verbose_name=‘类型‘)
如果不在model里定义,在modelForm里实现,利用labels
class UserInfoModelForm(forms.ModelForm): class Meta: model = models.UserInfo fields = "__all__" labels = ‘username‘:‘用户名‘, ‘email‘:‘邮箱‘,
指定需要展示的字段
fields = "__all__"
上面展示所有的,也可以展示指定的列
fields = [‘username‘,‘email‘] # 显示指定列 exclude = [‘username‘] # 排除指定列
错误信息
error_messages = ‘__all__‘: # 整体错误信息 , ‘email‘: ‘required‘: ‘邮箱不能为空‘, ‘invalid‘: ‘邮箱格式错误..‘,
给字段添加css属性
widgets = ‘username‘: Fwidgets.Textarea(attrs=‘class‘: ‘c1‘)
ModelForm的验证
跟form一样,ModleForm里面也有is_valid
,cleaned_data
,errors
,
# Form验证: UserInfoForm -> Form -> BaseForm( 包含is_valid等方法) # ModelForm验证: UserInfoModelForm -> ModelForm -> BaseModelForm -> BaseForm
ModelForm对数据库操作
添加数据
如果数据验证通过,直接调用save()方法,django会自动往数据库里添加一条数据(会根据modles里的字段一一对应)
if obj.is_valid(): obj.save() # 创建数据
如果在如下一对多、多对多关系中,如:
class UserType(models.Model): caption = models.CharField(max_length=32) class UserGroup(models.Model): name = models.CharField(max_length=32) class UserInfo(models.Model): username = models.CharField(max_length=32) email = models.EmailField() user_type = models.ForeignKey(to=‘UserType‘,to_field=‘id‘) u2g = models.ManyToManyField(UserGroup)
这样的话,执行上面的obj.save()
会自动在UserInfo表和多对多关系表里都增加数据,灰常灰常方便。
def index(request): if request.method == "GET": obj = UserInfoModelForm() return render(request,‘index.html‘,‘obj‘: obj) elif request.method == "POST": obj = UserInfoModelForm(request.POST) if obj.is_valid(): obj.save() # 等价以下三句 # instance = obj.save(False) # instance.save() # obj.save_m2m() return render(request,‘index.html‘,‘obj‘: obj)
修改数据
修改表数据是,记得把instance
信息也传进去,如:mf = UserInfoModelForm(request.POST,instance=user_obj)
不然是新建数据,而不是对某行数据进行修改。
编辑用户信息,新url方式保留默认数据
urls.py
url(r‘^user_list/‘, views.user_list), url(r‘^edit-(\d+)/‘, views.user_edit),
views.py
def user_list(request): li = models.UserInfo.objects.all().select_related(‘user_type‘) # 这里只能是外键,多对多字段也不可以 return render(request,‘user_list.html‘,‘li‘: li) def user_edit(request, nid): # 获取当前id对象的用户信息 # 显示用户已经存在数据 if request.method == "GET": user_obj = models.UserInfo.objects.filter(id=nid).first() mf = UserInfoModelForm(instance=user_obj) # 把默认数据传递进去 return render(request,‘user_edit.html‘,‘mf‘: mf, ‘nid‘: nid) elif request.method == ‘POST‘: # 数据修改的信息,给数据库的哪一行做修改? user_obj = models.UserInfo.objects.filter(id=nid).first() mf = UserInfoModelForm(request.POST,instance=user_obj) # 指定给谁做修改 if mf.is_valid(): mf.save() else: print(mf.errors.as_json()) return render(request,‘user_edit.html‘,‘mf‘: mf, ‘nid‘: nid)
user_list.html
<body> <ul> % for row in li % <li> row.username - row.user_type.caption - <a href="/edit- row.id /">编辑</a></li> % endfor % </ul> </body>
user_edit.html
<body> <form method="POST" action="/edit- nid /"> % csrf_token % mf.as_p <input type="submit" value="提交" /> </form> </body>
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