SelectField选项使用WTForms动态填充TextAreaField中的默认值 [英] SelectField option to dynamically populate default value in TextAreaField using WTForms

问题描述

我有一个从数据库表填充的SelectField.我将选择内容加载到表单中，如下所示:

I have a SelectField that is populated from a database table. I load the choices into the form as follows:

@statuses.route('/new', methods=['GET', 'POST'])
@login_required
def new_status():
    form = StatusForm()
    form.status_cd.choices = [(a.id, a.status_cd) for a in \
                               Status_Code.query.order_by('status_cd')]
    if form.validate_on_submit():
        status = Status(author=current_user)
        form.to_model(status)
        db.session.add(status)
        db.session.commit()
        flash('The status was added successfully.')
        return redirect(url_for('.index'))
    return render_template('statuses/new_status.html', form=form)  

查询中引用的模型如下:

The model referenced in the query is as follows:

class Status_Code(db.Model):
    __tablename__ = 'status_cd'
    id = db.Column(db.Integer, primary_key=True)
    status_cd = db.Column(db.String(16), nullable=False)
    status_detail = db.Column(db.Text)
    is_option_active = db.Boolean()
    date_created = db.Column(db.DateTime, default=db.func.now())

表单类如下:

class StatusForm(Form):
    datetime = DateTimeField('Date / Time')
    name = StringField('Name', validators=[Required()])
    status_cd = SelectField('Status Code', coerce=int)
    status_detail = TextAreaField('Status Detail', default="Default text",\
                                validators=[Required()])
    submit = SubmitField('Submit')

问题

根据SelectField中选择的选项，我希望它动态设置status_detail TextAreaField的默认文本.SelectField中的值应查询数据库并返回status_detail，它应为默认文本.

Depending on the option selected in the SelectField, I want it to dynamically set the status_detail TextAreaField's default text. The value from the SelectField should query the database and return the status_detail, which should be the default text.

例如，如果我有:

id   status_cd     status_detail
1    Apple         The apples are red.
2    Banana        The bananas are yellow. 

如果用户选择苹果"选项，则默认文本应为苹果为红色".

If the user selects the "Apple" option, the default text should be "The apples are red."

任何帮助将不胜感激！我正在构建我的第一个Flask应用程序，所以我对此并不陌生.

Any assistance would be greatly appreciated! I am building my first Flask app so I'm new to this.

推荐答案

以我对flask的经验，您可以通过两种方法来实现.没有正确的方法，这完全取决于您:

In my experience with flask, you can do this a couple of ways. There is no right way, and it is all up to you:

您可以加载status_detail数据，并将其放在选择选项值的data-detail标记中:

You can load the status_detail data, and place it in a data-detail tag in your select option value:

<select name='status_cd' onchange="get_status(this);">
    {% for s in status %}
        <option value='{{ s.id }}' data-detail='{{ s.status_detail }}'>{{ s.status_cd }} </option>
    {% endfor %}
</select>

然后，您可以使用JavaScript进行一次onchange，然后可以获取数据详细信息值并更新您的文本框(这是伪代码，并非用于复制和粘贴):

Then you can do an onchange with JavaScript, which can then get the data-detail value and update your text box (this is pseudo code, not meant for copy and paste):

<script>
    function onchange(o){
      var value = $(o).attr('data-detail');
      //do something with the value
   }
</script>

OR

如果不希望将data-detail标记放入代码中，则可以动态地从数据库中提取数据，例如:

You can do it where it pulls from the database dynamically if you don't wan to put the data-detail tag in your code, like this:

与JavaScript的onchange相同，但是随后可以调用您的路由方法的Ajax调用以返回您的值(这是伪代码，不是用于复制和粘贴):

Same onchange with JavaScript, but can then do a call to an Ajax call to your routed method to return your value (this is pseudo code, not meant for copy and paste):

<script>
    function onchange(o){
      var value = $(o).value();
    $.ajax({
      url: '/my_rout',
      data: value,
      success : function(data){
        //handle your result here
      }
   })
   }
</script>

我希望这至少可以为您提供正确的方向，并提供一些不同的选择.

I hope this at least gets you in the right direction with some different options to choose from.

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