Flask/Jinja2 动态 WTF 表单模板

Question

I am trying to create a jinaj2 template with a dynamic number of input fields.

The form is generating successfully in Flask, however I am having issues with the Jinja/HTML.

As an example of my "non-dynamic" working example I have one standard form field "forID" and and four hard coded field forms field+(field number).

{{ form.csrf_token }}
{{ wtf.form_field(form.formID) }}

{{ wtf.form_field(form.field1) }}
{{ wtf.form_field(form.field2) }}
{{ wtf.form_field(form.field3) }} 
{{ wtf.form_field(form.field4) }}

What method can I use to make the Jinja/HTML dynamic. I have tried EVAL and EVEC, but these Python commands are not supported in Jinja.

#<form method="POST" action = "{{url_for('myHtmlTemplate')}}">
{{ form.csrf_token }}
{{ wtf.form_field(form.formID) }}

{% for i in form.myDynamicFields.keys() %}:
     {{ eval(' wtf.form_field(form.'+'i')') }}
{% endfor %}    

<input class="btn btn-success" type="submit" value="Submit">
#</form>

My current myForm.

class myform(FlaskForm):
connection = removed
result = connection.execute("SELECT * FROM sqltable")
result = result.fetchall()

scenarioList = []
fieldList = []
fieldLabel = []

for scen in result:
scenarioList.append("Scenario: " + scen[0])
fieldList.append("field: " + scen[0])

for i in range(len(result)):
fieldLabel.append("My Field" + str(i + 1))

myDynamicFields = dict(zip(fieldLabel, fieldList))
formID = StringField('Form ID')

for key, val in myDynamicFields.items():
exec(key + '=StringField(val)')

Answer 1

' wtf.form_field(form.'+'i')' has an odd number of apostrophes which is a syntax problem

I'm guessing you want something closer to:

' wtf.form_field(form.' + i + ')'

So that you get

i = 'your_field'
print(' wtf.form_field(form.' + i + ')')

wtf.form_field(form.your_field)

---

I do agree with @DanielRoseman's comment. I would probably approach the problem more like the following (if it works with your implementation):

{% for field in form.myDynamicFields %}:
     {{ wtf.form_field(field) }}
{% endfor %} 

Answer 2

I did not manage to use the method of iterating the dictionary discussed above, although if it could work I agree it would be much more elegant.

However, I have a work around. Generating the HTML as a text string in my form instance, starting with a template and dynamically building up the section Jinja2 could not evaluate without errors. I pass this HTML string out the class into the render function.

In the meantime I'll contact the Jinja2 development team to see how it could be done within the template itself.