# 后端
def realreg(request):
    error = {‘username‘:‘‘,‘password‘:‘‘} # 定义一个字典存储错误信息
    if request.method == ‘POST‘:
        username = request.POST.get(‘username‘)
        password = request.POST.get(‘password‘)
    if len(password) < 6:
        error[‘password‘] = ‘密码不能小于6位‘
    return render(request,‘reg.html‘,{‘error‘:error})

# 前端
<input type=‘text‘ name=‘username‘>
<span>{{ error.username }}</span>
<input type=‘text‘ name=‘password‘>
<span>{{ error.password }}</span>

from django import forms

class MyForm(forms.Form):
name = forms.CharField(max_length=6)
password = forms.CharField(max_length=8,min_length=3)
email = forms.EmailField(required=True)

form_obj = MyForm({‘name‘:‘moonzier‘，‘password‘:‘123‘,‘email‘:‘haha@163.com‘}) # 传入字典

form_obj.is_valid() # 只有当所有的字段都校验通过才会返回True

form_obj.errors # 这个里面放的是所有校验未通过的字段及错误提示
"""
{
‘name‘: [‘Ensure this value has at most 6 characters (it has 7).‘], 
‘password‘: [‘Ensure this value has at least 3 characters (it has 2).‘], 
‘email‘: [‘Enter a valid email address.‘]
}
"""

form_obj.cleaned_data # 符合校验规则数据都会被放到该对象中

# 前端取消校验
<form action="" method="post" novalidate>
</form>

{{ form_obj.as_p }} <!--作为<p>标签形式渲染-->
{{ form_obj.as_ul }} 

<form action="">
<p>{{ form_obj.name.label }}{{ form_obj.name }}</p> <!--若后端并没有定义name属性，则将字段的首字母大写作为label的值-->
<p>{{ form_obj.password.label }}{{ form_obj.password }}</p>
<p>{{ form_obj.email.label }}{{ form_obj.email }}</p>
<input type="submit">
</form>

<form action="">
{% for foo in form_obj %}
<p>{{ foo.label }}{{ foo }}</p>
{% endfor %}
</form>

from django import forms
from django.forms import widgets
password = forms.CharField(max_length=8,
                           min_length=3,
                           error_messages={
                               ‘max_length‘: ‘密码最长8位‘,
                               ‘required‘: ‘密码不能为空‘,
                               ‘min_length‘:‘密码最少3位‘
                           },
                           widget=widgets.PasswordInput(attrs={‘class‘:‘c1 form-control‘}))  # widgets.PasswordInput密码密文显示，attr增加字段

# 后端
# 定义form类
class MyForm(forms.Form):
    name = forms.CharField(max_length=6,
                           label=‘用户名‘,  # 前端label标签可获得label属性的值
                           error_messages={
                                            ‘max_length‘:‘用户名最长6位‘,
                                            ‘required‘:‘用户名不能为空‘
                                        }  # 自定义错误提示信息，可更改成中文
                         )
    
def reg(request):
    # 生成一个空对象
    form_obj = MyForm()
    if request.method == ‘POST‘:
        form_obj = MyForm(request.POST)  # request.POST就是一个字典，传入自动校验数据，并且发生错误不清空数据
        if form_obj.is_valid():
            models.User.objects.create(**form_obj.cleaned_data)  # 在使用form组件对模型表进行数据校验的时候，只需要保证字段一致
        那么在创建的对象的时候你就直接**form_obj.cleaned_data
    return render(request,‘reg.html‘,locals())

# 前端
<form action="" method="post" novalidate>
    {% for foo in form_obj %}
        <p>
        {{ foo.label }}{{ foo }}
        <span>{{ foo.errors.0 }}</span>  #只取第一个错误
        </p>
    {% endfor %}
    <input type="submit">
</form>

# 校验name字段，如果出现666就报错
def clean_name(self):
    name = self.cleaned_data.get(‘name‘)
    if ‘666‘ in name:
        self.add_error(‘name‘,‘光喊666是不行的，要有真实力!‘)
    return name # return还是要加上的，兼容性考虑    

# 校验password和confirm_password是否一致，不一致就报错
def clean(self):
    password = self.cleaned_data.get(‘password‘)
    confirm_password = self.cleaned_data.get(‘confirm_password‘)
    if not password == confirm_password:
        self.add_error(‘confirm_password‘,"两次密码不一致!")
    return self.cleaned_data