Python菜鸟之路：Django ModelForm的使用

一、简单使用案例

#views.py
#views.py
from django.shortcuts import render,HttpResponse
from app01 import models

from django import forms
from django.forms import fields as Ffields
from django.forms import widgets as Fwidgets
class UserInfoModelForm(forms.ModelForm):

    is_rmb = Ffields.CharField(widget=Fwidgets.CheckboxInput())

    class Meta:
        model = models.UserInfo
        fields = '__all__'
        # fields =  ['username','email']
        # exclude = ['username']
        labels = {
            'username': '用户名',
            'email': '邮箱',
        }
        help_texts = {
            'username': '...'
        }
        widgets = {
            'username': Fwidgets.Textarea(attrs={'class': 'c1'})
        }
        error_messages = {
            '__all__':{

            },
            'email': {
                'required': '邮箱不能为空',
                'invalid': '邮箱格式错误..',
            }
        }
        field_classes = {
            # 'email': Ffields.URLField
        }

        # localized_fields=('ctime',)

    def clean_username(self):
        old = self.cleaned_data['username']
        return old

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() 等效于下面的3条
            instance = obj.save(False)
            instance.save()  # 这样的话只会保存当前的类到数据库，并不会保存关联的多对多关系到U2G表中
            obj.save_m2m()  # 保存many to many的关系到数据库


        # print(obj.is_valid())
        # print(obj.cleaned_data)
        # print(obj.errors.as_json())
        return render(request,'index.html',{'obj': obj})

　　

　　

#models.py
from django.db import models

# Create your models here.


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)

　　

　   总结： 从上边可以看到ModelForm用起来也是非常方便的，比如增加修改之类的操作。但是也带来额外不好的地方，model和model之间耦合了。如果不耦合的话，mf.save()方法也无法直接提交保存。 但是耦合的话使用场景通常局限用于小程序，写大程序就最好不用了