Python 如何修复str对象没有属性“\u meta”

我正在Django项目中迁移我的模型，但正在生成错误。下面是代码。要解决这个问题，我的代码中应该有哪些更正

Models.py
from django.db import models
from django.contrib.auth.models import User

# Create your models here.
class UserProfileInfo(models.Model):

    user = models.OneToOneField(User, on_delete=models.CASCADE)

    #addtional
    portfolio_site = models.URLField(blank=True)

    profile_pic = models.ImageField(blank=True,upload_to="profile_pics")

    def __str__(self):
        return (self.user.username)

我越来越 属性错误：“str”对象没有属性“\u meta”

的参数是一个模型，或一个模型的iterable；和可选的模型管理员。不是那种类型的字符串

因此，应该传递对UserProfileInfo的引用，而不是包含该名称的字符串

比如：

---

无需使用字符串包装模型，只需在admin.py中键入模型名称

---

阅读手册可能有助于：

Forms.py
from django import forms
from django.contrib.auth.models import User
from basic_app.models import UserProfileInfo

class UserForm(forms.ModelForm):
    password = User.CharField(widget=forms.PasswordInput())

    class Meta():
        model = User
        fields = ['username','email', 'password']


class UserProfileInfo(forms.ModelForm):
    class Meta():
        model = UserProfileInfo
        fields=['portfolio_site','profile_pic']     

Admin.py
from django.contrib import admin
from basic_app.models import UserProfileInfo


# Register your models here.
admin.site.register('UserProfileInfo')

# app/admin.py

from django.contrib import admin
from basic_app.models import UserProfileInfo

# an identifier, not a string
admin.site.register(UserProfileInfo)

Admin.py
from django.contrib import admin
from basic_app.models import UserProfileInfo


# Register your models here.
admin.site.register(UserProfileInfo)