form = UserForm()
user = User.query.from_db()
form.usernme.data = user.username
form.bio.data = user.bio

def index():
    form = MyForm()
    return render_template(‘index.html’, form=form)

以下
app.py代码：
from flask_bootstrap import Bootstrap
from flask import Flask,render_template

from flask_sqlalchemy import SQLAlchemy

import config

app = Flask(__name__)
bootstrap = Bootstrap(app)
@app.route(‘/’)
def index():
return render_template(‘index.html’)

index.html代码：
{% from ‘bootstrap/form.html’ import render_field, render_hidden_errors %}

{{ form.hidden_tag() }}
{{ render_hidden_errors(form) }}
{{ render_field(form.username) }}
{{ render_field(form.password) }}
{{ render_field(form.submit) }}

pip uninstall bootstrap-flask flask-bootstrap
pip install bootstrap-flask