动态选择WTForms Flask SelectField [英] Dynamic choices WTForms Flask SelectField

问题描述

我正在尝试通过FlaskForms将userID变量传递给WTForms.首先，我将显示可以正常工作的代码，然后显示需要修改的内容(我不知道该如何做的部分).我要添加与某个组关联的新名称.

I'm trying to pass userID variable to WTForms with FlaskForms. First I'll show code that works fine and then what I need to modify(that the part I don't know how). I'm adding new Name associated with some group.

FlaskForm模型:

class AddName(FlaskForm):
    name =StringField('Device name', validators=[InputRequired(),Length(min=4, max=30)])
    groupID = SelectField('Payload Type', choices=[(1,"Group1"),(2,"Group2")], validators=[InputRequired])

查看模型:

@app.route('/dashboard/addname', methods=['GET', 'POST'])
def addname():
    form=AddName()
    if form.validate_on_submit():
        name=Name(form.name.data,form.groupID.data)
        db.session.add(name)
        db.session.commit()
        return "New name added"

模板:

              <form method="POST" action="/dashboard/addname">
                  <h2>Add name</h2>
                  {{ form.hidden_tag() }}
                  {{ wtf.form_field(form.name) }}
                  {{ wtf.form_field(form.groupID) }}
                  <button type="submit">Add name</button>
              </form>

我在下拉列表中看到正确的列表，并且在提交时给了我正确的数字.

I see correct list in dropdown, and on submit gives me correct numbers.

任务:我需要基于 current_user.userID 传递不同的列表. 我正在使用SQLAlchemy通过从数据库表中查询来形成列表，所以我的 Flask视图是:

Task: I need to pass different list based on current_user.userID. I'm forming list using SQLAlchemy, by making query from table from DB, so My Flask view is:

@app.route('/dashboard/addname', methods=['GET', 'POST'])
def addname():
    available_groups=db.session.query(Groups).filter(Groups.userID == currend_user.userID).all()
    #Now forming the list of tuples, so it's ok for SelectField
    groups_list=[(i.groupID, i.groupName) for i in available_groups]
    form=AddName()
    if form.validate_on_submit():
        name=Name(form.name.data,form.groupID.data)
        db.session.add(name)
        db.session.commit()
        return "New name added"

1. 如何将我的 groups_list 传递给表单?我试图在FlaskForm模型中实现形成过程，但是看不到current_user对象
2. 当我需要将groupID像元组一样传递给SelectField时，是否需要将groupID转换为 string ，然后又转换回 int ?

1. How can i pass my groups_list to the form? I tried to implement forming procedure in the FlaskForm model, but it doesn't see current_user object
2. Do I need to transform groupID to string and then back to int when I need to pass it to the SelectField like tuples?

推荐答案

此处的主要思想是在实例化之后将选择列表分配给字段.为此，您需要使用参数coerce=int. SelectField的coerce关键字arg表示我们使用int()来强制转换表单数据.默认强制为unicode().

The main idea here is to assign the choices list to the field after instantiation. To do so you need to use argument coerce=int. The coerce keyword arg to SelectField says that we use int() to coerce form data. The default coerce is unicode().

更正FormModel:

class AddName(FlaskForm):
    name =StringField('Device name', validators=[InputRequired(),Length(min=4, max=30)])
    groupID = SelectField('Payload Type', coerce=int, validators=[InputRequired])

正确的视图:

@app.route('/dashboard/addname', methods=['GET', 'POST'])
def addname():
    available_groups=db.session.query(Groups).filter(Groups.userID == currend_user.userID).all()
    #Now forming the list of tuples for SelectField
    groups_list=[(i.groupID, i.groupName) for i in available_groups]
    form=AddName()
    #passing group_list to the form
    form.groupID.choices = groups_list
    if form.validate_on_submit():
        name=Name(form.name.data,form.groupID.data)
        db.session.add(name)
        db.session.commit()
        return "New name added"

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