表单值未添加到 Flask 中的数据库中

Question

我之前发布了这个问题，但它随后被链接到一个类似的问题，该问题没有提供所需的解决方案，然后被关闭以供回答。因此，我创建了一个 Flask 应用程序，它跟踪产品从一个位置到另一个位置的移动，同时我通过 Flask 应用程序进行移动，表单没有得到验证我尝试添加并添加到从用户那里获取输入的 html{{ form.hidden_tag() }}文件{{ form.csrf_token }}。如果我从终端在我的命令行上运行这个应用程序，表单会被验证并被添加到数据库中，但是如果我运行 flask 应用程序并在浏览器中提交表单，它不会。这是我的代码class MovementForm(FlaskForm):    to_location = SelectField('To Location', coerce=int)    from_location = SelectField('From Location', coerce=int)    product = SelectField('Product')    quantity = IntegerField('Quantity')    add_movement = SubmitField('Add Movement')@app.route('/movements',methods=["GET","POST"])def add_movements():    form = MovementForm()    form.to_location.choices = [(location.id, location.location_name) for location in Location.query.all()]    form.from_location.choices = [(location.id, location.location_name) for location in Location.query.all()]    form.product.choices = [(product.id, product.product_name) for product in Product.query.all()]    form.from_location.choices.insert(0, (0, 'None'))       if form.validate_on_submit():        new_movement = Movement(to_location_id=form.to_location.data, from_location_id=form.from_location.data, product_id=form.product.data, quantity=form.quantity.data)        db.session.add(new_movement)        db.session.commit()        flash('Product has been moved!', 'success')        return redirect(url_for('add_movements'))       return render_template('add_movements.html', form=form)这里出了什么问题？

Answer 1

尝试在 HTML 表单中删除更改表单的操作。

 <form action="" method="post">

    {{ form.hidden_tag() }}

    {{ form.csrf_token }}

    <div class="row">

        <div class="form-group col">

            {{ form.from_location.label(class="form-control-label") }}

            {{ form.from_location(class="form-control form-control-lg") }}

        </div>

        <div class="form-group col">

            {{ form.to_location.label(class="form-control-label") }}

            {{ form.to_location(class="form-control form-control-lg") }}

        </div>

    </div>

    <div class="row">

        <div class="form-group col">

            {{ form.product.label(class="form-control-label") }}

            {{ form.product(class="form-control form-control-lg") }}

        </div>

        <div class="form-group col">

            {{ form.quantity.label(class="form-control-label") }}

            {{ form.quantity(class="form-control form-control-lg") }}

        </div>

    </div>

    <div class="form-group">

            {{ form.add_movement(class="btn btn-outline-info") }}

    </div>

</form> 

这能解决问题吗？

此外，我建议您将 Flash 消息添加到 HTML 中，因为我看到一旦提交表单，它就会返回到“add_movements”函数。因此添加：

 <div>

     {% for msg in get_flashed_messages%}

         <h1>{{msg}}</h1>

     {% endfor %}

 </div>

 <form action="" method="post">

{{ form.hidden_tag() }}

{{ form.csrf_token }}

<div class="row">

    <div class="form-group col">

        {{ form.from_location.label(class="form-control-label") }}

        {{ form.from_location(class="form-control form-control-lg") }}

    </div>

    <div class="form-group col">

        {{ form.to_location.label(class="form-control-label") }}

        {{ form.to_location(class="form-control form-control-lg") }}

    </div>

</div>

<div class="row">

    <div class="form-group col">

        {{ form.product.label(class="form-control-label") }}

        {{ form.product(class="form-control form-control-lg") }}

    </div>

    <div class="form-group col">

        {{ form.quantity.label(class="form-control-label") }}

        {{ form.quantity(class="form-control form-control-lg") }}

    </div>

</div>

<div class="form-group">

        {{ form.add_movement(class="btn btn-outline-info") }}

</div>

＃编辑

我注意到一旦强制丢失，产品字段中就缺少了一些东西：

class MovementForm(FlaskForm):

    to_location = SelectField('To Location', coerce=int)

    from_location = SelectField('From Location', coerce=int)

    product = SelectField('Product', coerce=int)

    quantity = IntegerField('Quantity')

    add_movement = SubmitField('Add Movement')

编辑#2

如果您遇到此类问题（这种情况经常发生），我建议您也添加打印语句和 If/Else 子句。这将极大地帮助您解决问题所在（您发布的问题类型的问题是您“看不到”）并且会给您“眼睛”。

例如，这就是我会做的：

@app.route('/movements',methods=["GET","POST"])

def add_movements():

    form = MovementForm()

    form.to_location.choices = [(location.id, location.location_name) for 

    location in Location.query.all()]

    form.from_location.choices = [(location.id, location.location_name) 

    for location in Location.query.all()]

    form.product.choices = [(product.id, product.product_name) for product 

    in Product.query.all()]

    form.from_location.choices.insert(0, (0, 'None')) 

    if form.validate_on_submit():

        print('Form Ok') #if you see the 'Form ok' to see if is validated

        new_movement = Movement(to_location_id=form.to_location.data, 

        from_location_id=form.from_location.data, 

        product_id=form.product.data, quantity=form.quantity.data)

        db.session.add(new_movement)

        db.session.commit()

        flash('Product has been moved!', 'success')

        return redirect(url_for('add_movements'))

     else:

         print('Form Not Ok') #If you see this printed then you see that 

          #is not validated

return render_template('add_movements.html', form=form)