如何在Django的forms.py中为PasswordInput字段添加类？

嘿，我刚好遇到过一模一样的问题！原因其实很简单：UserCreationForm本身已经显式定义了password1和password2这两个字段，它们并不是User模型自带的字段，所以你在Meta类的widgets字典里配置这两个字段是不会生效的。

别担心，有两种简单的方法可以解决这个问题：

方法一：重新定义密码字段 #

直接在表单类里重新声明password1和password2字段，同时指定带form-control类的PasswordInput widget：

from django import forms
from django.forms import TextInput, PasswordInput
from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth.models import User

class SignUpForm(UserCreationForm):
    # 重新定义密码字段，添加Bootstrap样式类
    password1 = forms.CharField(
        label="Password",
        widget=PasswordInput(attrs={'class':'form-control'}),
    )
    password2 = forms.CharField(
        label="Password confirmation",
        widget=PasswordInput(attrs={'class':'form-control'}),
    )

    class Meta:
        model = User
        fields = ('username', 'first_name', 'last_name', 'email', 'password1', 'password2',)
        widgets = {
            'username': TextInput(attrs={'class':'form-control'}),
            'first_name': TextInput(attrs={'class':'form-control'}),
            'last_name': TextInput(attrs={'class':'form-control'}),
            'email': TextInput(attrs={'class':'form-control'}),
        }

方法二：重写表单的__init__方法（推荐） #

这种方法不用重复定义字段，直接在表单初始化的时候修改现有字段的widget属性，还能保留UserCreationForm自带的密码验证逻辑：

from django import forms
from django.forms import TextInput, PasswordInput
from django.contrib.auth.forms import UserCreationForm
from django.contrib.auth.models import User

class SignUpForm(UserCreationForm):
    class Meta:
        model = User
        fields = ('username', 'first_name', 'last_name', 'email', 'password1', 'password2',)
        widgets = {
            'username': TextInput(attrs={'class':'form-control'}),
            'first_name': TextInput(attrs={'class':'form-control'}),
            'last_name': TextInput(attrs={'class':'form-control'}),
            'email': TextInput(attrs={'class':'form-control'}),
        }

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        # 给两个密码字段添加form-control类
        self.fields['password1'].widget.attrs.update({'class': 'form-control'})
        self.fields['password2'].widget.attrs.update({'class': 'form-control'})

两种方法都能让密码输入框成功带上form-control类，方法二更简洁，也不会破坏原有表单的验证逻辑，我个人更推荐这种~

内容的提问来源于stack exchange，提问作者Justin