Django之ModelForm(一)

要说ModelForm,那就先说Form吧!

先给出一个Form示例:

models.py
from django.db import models

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(verbose_name="用户",max_length=32)
    email=models.EmailField()
    user_type=models.ForeignKey(to='UserType',to_field="id",on_delete=models.CASCADE)  #关联UserType  一对一
    u2g=models.ManyToManyField(UserGroup)  #关联UserGroup 多对多

views.py
from django.shortcuts import render
from django import  forms
from django.forms import fields
from app_01 import models

class UserInfoForm(forms.Form):
    username = fields.CharField(max_length=32)
    email = fields.EmailField()
    user_type = fields.ChoiceField(
        choices=models.UserType.objects.values_list("id","caption")  #在页面上 把用户类型作为列表列上来了
    )

    def __init__(self,*args,**kwargs):            #自动更新操作
        super(UserInfoForm,self).__init__(*args,**kwargs)
        self.fields['user_type'].choices=models.UserType.objects.values_list("id","caption")


def index(request):
    if request.method=="GET":
        obj=UserInfoForm()
        return render(request,"index.html",{'obj':obj})

    elif request.method=="POST":
        obj=UserInfoForm(request.POST)
        if obj.is_valid() :
            obj.save()     #验证成功 把所有的正确信息保存在数据库中

        return render(request,'index.html',{'obj':obj})

index.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/index/" method="post">
        {{ obj.as_p}}
        {% csrf_token %}
        <input type="submit" value="提交" />
    </form>

</body>
</html>

在html上显示的效果为:

看了上面的示例,觉不觉得特麻烦?那让我们现在用ModelForm来实现吧!

其他不用改,只改views.py文件

from django.shortcuts import render
from django import  forms
from django.forms import fields
from app_01 import models

class UserInfoModelForm(forms.ModelForm):

    class Meta:
        model=models.UserInfo
        fields="__all__"   #代指所有的字段
    # models.UserInfo.objects.create(**obj.cleaned_data)   #在数据库中自动进行创建
    # models.UserInfo.objects.filter(id=1).update(**obj.cleaned_data) #在数据库中自动进行更新

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() #验证成功 把所有的正确信息保存在数据库中 return render(request,'index.html',{'obj':obj})

 

可以看到Form和ModelForm的区别了吧!

但是ModelForm也有弊端的,只能用它写小一点的程序,而大程序利用这个则不适用!

利用ModelForm来实践下吧!

Models.py
from django.db import models

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(verbose_name="用户",max_length=32)
    email=models.EmailField()
    user_type=models.ForeignKey(to='UserType',to_field="id",on_delete=models.CASCADE)
    u2g=models.ManyToManyField(UserGroup)


Views.py
def user_list(request):
    li=models.UserInfo.objects.all().select_related('user_type') #可以拿到UserInfo表内的数据,也可以拿到UserType表内的数据
    return render(request,'user_list.html',{'li':li})


def user_edit(request,nid):
    if request.method=="GET":
        user_obj=models.UserInfo.objects.filter(id=nid).first()
        mf=UserInfoModelForm(instance=user_obj)  #这里不能瞎传 必须得有参数 instance   若无instance 则是在数据库内创建了一条数据,而不是直接对数据进行更改
        return render(request,'user_edit.html',{'mf':mf ,'nid':nid})
    elif request.method=="POST":
        user_obj = models.UserInfo.objects.filter(id=nid).first()
        mf = UserInfoModelForm(request.POST,instance=user_obj)
        if mf.is_valid():    #正确信息全部拿到
            mf.save()        #保存至数据库里
        else:
            print(mf.errors.as_json())
            return render(request, 'user_edit.html', {'mf': mf, 'nid': nid})

user_list.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<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>
</html>

user_edit.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <form action="/edit-{{ nid }}/" method="post">
        {% csrf_token %}
        {{ mf.as_p }}
        <input type="submit" value="提交" />
    </form>
</body>
</html>

urls.py
from django.contrib import admin
from django.urls import path
from app_01 import views
from django.conf.urls import url
import re
urlpatterns = [
    path('admin/', admin.site.urls),
    path('index/', views.index),
    path('user_list/', views.user_list),
    url(r'^edit-(d+)/', views.user_edit)  #正则表达式
]

user_list上的操作效果为:

user_erit上的操作效果为

原文地址:https://www.cnblogs.com/zhuifeng-mayi/p/9129345.html