我在这里看到了一些类似的问题，但是似乎没有一种解决方案适用于此（问题通常是它缺少一个csrf令牌，在这里不是这种情况）。
我有一个包含四个字段的表单-3个带有SelectField的下拉列表和一个String-15-使用flask wtforms构建的表单。我尝试为此添加一个编辑功能，该功能使用相同的HTML模板，但是此功能尚未通过验证（未输入form.validate_on_submit部分）。这是该函数的代码：
@app.route('/movements/<int:movement_id>/edit', methods=['GET', 'POST'])
def edit_movement(movement_id):
movement = Movement.query.get_or_404(movement_id)
form = MovementForm()
if form.validate_on_submit():
product = Product.query.filter_by(id=form.product.data).first()
from_location = Location.query.filter_by(id=form.from_location.data).first()
to_location = Location.query.filter_by(id=form.to_location.data).first()
if int((Balance.query.filter_by(product = product.name).filter_by(location = from_location.name).first()).balance) < int(form.quantity.data) and from_location.name != "":
flash("Invalid movement. Quantity of the product is insufficient.")
else:
movement.product_id = product.id
movement.product = product.name
movement.from_location_id = from_location.id
movement.from_location = from_location.name
movement.to_location_id = to_location.id
movement.to_location = to_location.name
movement.quantity = form.quantity.data
db.session.commit()
flash('The product movement has been edited!', 'success')
return redirect(url_for('movements'))
elif request.method == 'GET':
form.product.choices = [(product.id,product.name) for product in Product.query.all()]
form.from_location.choices = [(location.id,location.name) for location in Location.query.all()]
form.to_location.choices = [(location.id,location.name) for location in Location.query.all()]
form.quantity.data = movement.quantity
edit_button = True
return render_template('movements.html',form=form, edit_button=edit_button)
这是表单的代码：
class MovementForm(FlaskForm):
product = SelectField("Product", choices = [])
from_location = SelectField("From Location", choices = [], coerce=int)
to_location = SelectField("To Location", choices = [], coerce=int)
quantity = StringField("Quantity", validators=[DataRequired()])
add_movement = SubmitField("Add Movement")
这是表格的模型：
class Movement(db.Model):
id = db.Column(db.Integer, primary_key=True)
product_id = db.Column(db.Integer, db.ForeignKey('product.id'), nullable=False)
product = db.Column(db.String(50), nullable=False)
from_location_id = db.Column(db.Integer, db.ForeignKey('location.id'))
from_location = db.Column(db.String(50))
to_location_id = db.Column(db.Integer, db.ForeignKey('location.id'))
to_location = db.Column(db.String(50))
quantity = db.Column(db.Integer, nullable=False)
timestamp = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
表单的HTML代码：
<form action="" method="POST">
{{ form.csrf_token }}
{{ form.product.label }}
{{ form.product }}
{{ form.from_location.label }}
{{ form.from_location }}
{{ form.to_location.label }}
{{ form.to_location }}
{{ form.quantity.label }}
{{ form.quantity }}
{% if edit_button %}
<input type="submit" value="Edit Movement">
{% else %}
{{ form.add_movement }}
{% endif %}
</form>
答案 0 :(得分：1)
validate_on_submit是一项便捷的功能，它结合了对表单是否已提交的检查（即POST，PUT，PATCH或DELETE）和对form.validate的调用。如果验证失败，则form.errors持有的字典将填充有用的信息。
调试问题的一个有用步骤是，如果form.errors返回False，则记录（打印）validate_on_submit的内容。
答案 1 :(得分：1)
您的代码中的form.errors如下：
{'product': ['Not a valid choice'], 'from_location': ['Not a valid choice'], 'to_location': ['Not a valid choice']}
因此，validate_on_submit返回False是合理的。
如果您注释掉这些字段并仅保留应该工作的数量。以下更改对我有用，我设法更新了数据库中的数量。如果它也对您有用，那么您可以尝试取消注释每个字段并进一步调试。
将表单更改为：
class MovementForm(FlaskForm):
quantity = StringField("Quantity", validators=[DataRequired()])
add_movement = SubmitField("Add Movement")
以及到达以下地点的路线
：@app.route('/movements/<int:movement_id>/edit', methods=['GET', 'POST'])
def edit_movement(movement_id):
movement = Movement.query.get_or_404(movement_id)
form = MovementForm()
if form.validate_on_submit():
movement.quantity = form.quantity.data
db.session.commit()
flash('The product movement has been edited!', 'success')
return redirect(url_for('movements'))
elif request.method == 'GET':
form.quantity.data = movement.quantity
print(form.errors)
edit_button = True
return render_template('movements.html', form=form, edit_button=edit_button)
将模板更改为：
<form action="" method="POST">
{{ form.csrf_token }}
{{ form.quantity.label }}
{{ form.quantity }}
{% if edit_button %}
<input type="submit" value="Edit Movement">
{% else %}
{{ form.add_movement }}
{% endif %}
</form>
更新：
here说明了您面临的问题。
请尝试以下操作，如果它能按预期工作，则对其余字段进行类似设置（它对我有用，我设法更新了数据库中的数量和from_location / id）：
表格：
class MovementForm(FlaskForm):
fromloc = [(location.id,location.name) for location in Location.query.all()]
from_location_id = SelectField("From Location ID", choices = fromloc, coerce=int)
quantity = StringField("Quantity", validators=[DataRequired()])
add_movement = SubmitField("Add Movement")
路线：
@app.route('/movements/<int:movement_id>/edit', methods=['GET', 'POST'])
def edit_movement(movement_id):
movement = Movement.query.get_or_404(movement_id)
form = MovementForm()
if form.validate_on_submit():
movement.from_location_id = form.from_location_id.data
movement.from_location = (Location.query.filter_by(id = form.from_location_id.data).first()).name
movement.quantity = form.quantity.data
db.session.commit()
flash('The product movement has been edited!', 'success')
return redirect(url_for('movements'))
elif request.method == 'GET':
form.from_location_id.choices = [(location.id,location.name) for location in Location.query.all()]
form.quantity.data = movement.quantity
print(form.errors)
edit_button = True
return render_template('movements.html', form=form, edit_button=edit_button)
模板：
<form action="" method="POST">
{{ form.csrf_token }}
{{ form.from_location_id.label }}
{{ form.from_location_id }}
{{ form.quantity.label }}
{{ form.quantity }}
{% if edit_button %}
<input type="submit" value="Edit Movement">
{% else %}
{{ form.add_movement }}
{% endif %}
</form>
答案 2 :(得分：0)
我仍然不太确定为什么我的表单没有通过验证，但是在我将if form.validate_on_submit()替换为if request.method == 'POST'之后，我的函数开始起作用了。