方法在我的应用程序上抛出BadRequestKeyError

Question

我不明白为什么我要在BadRequestKeyError: 400 Bad Request: KeyError: 'todoitem'路线上到达delete。

from flask import Flask, render_template, request, redirect, url_for
from flask_sqlalchemy import SQLAlchemy

app = Flask(__name__)

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///my_todo.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

class Todo(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    text= db.Column(db.String(200))
    complete= db.Column(db.Boolean)

@app.route('/delete/<int:id>')
def delete(id):
    todo = Todo(text=request.form['todoitem'], complete=False)
    todo = todo.query.filter_by(_id = id).first()
    db.session.delete(todo)
    db.session.commit()

    incomplete = Todo.query.filter_by(complete=False).all()
    complete = Todo.query.filter_by(complete=True).all()

    return render_template('index.html', incomplete=incomplete, complete=complete)

  <ul>
    {% for todo in complete %}
    <li>{{todo.text}}</li><a href="{{url_for('delete', id=todo.id)}}">  Deletar</a>
    {% endfor %}
  </ul>