jinja2.exceptions.UndefinedError：“render_field”未定义

Question

所以我刚刚开始Wtforms与 结合使用Flask，我设置了基本类并定义了我的所有字段，forms.py正如您在此处看到的那样......

from wtforms import Form, TextField, validators, PasswordField, DateField

class AddAccount(Form):
    username = TextField('Username', [validators.Length('min=3, max=20')])
    email = TextField('Email', [validators.Length('min=1, max=255')])
    karma = TextField('Karma', [validators.Length('min=1, max=10000000')])
    password = PasswordField('Password', [validators.Length('min=6, max=255')])

然后我将AddAccount类导入到views.py你可以在这里看到的......

from forms import AddAccount

@app.route('/dashboard/add', methods=['POST', 'GET'])
def add_account():

    form = AddAccount(request.form)

    if request.method == 'POST' and form.validate():
        print('POST request')


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

这是模板文件...

{% extends 'layout.html' %}

{% block body %}
    <br>
    <div class="jumbotron text-center">
       <h1>Add an Account</h1>
       <hr>
       <form action="{{url_for('add_account')}}">
            <div class="form-group">
                {{render_field(form.username, class_='form-control')}}
            </div>
            <div class="form-group">
                {{render_field(form.email, class_='form-control')}}    
            </div>
            <div class="form-group">
                {{render_field(form.password, class_='form-control')}}
            </div>
            <div class="form-group">
                {{render_field(form.karma, class_='form-control')}}
            </div>
        </form>
    </div>
{% endblock %}

整个装置导致了这个错误jinja2.exceptions.UndefinedError: 'render_field' is undefined，我完全不知道为什么会发生或者如何修复它。任何帮助将不胜感激。

如果有帮助的话...这是堆栈跟踪...

Traceback (most recent call last):
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1997, in __call__
    return self.wsgi_app(environ, start_response)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1985, in wsgi_app
    response = self.handle_exception(e)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1540, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\_compat.py", line 33, in reraise
    raise value
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1982, in wsgi_app
    response = self.full_dispatch_request()
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1614, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1517, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\_compat.py", line 33, in reraise
    raise value
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1612, in full_dispatch_request
    rv = self.dispatch_request()
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\app.py", line 1598, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "E:\Python\manager\views.py", line 37, in add_account
    return render_template('add_account.html', form=form)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\templating.py", line 134, in render_template
    context, ctx.app)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\flask\templating.py", line 116, in _render
    rv = template.render(context)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\jinja2\asyncsupport.py", line 76, in render
    return original_render(self, *args, **kwargs)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\jinja2\environment.py", line 1008, in render
    return self.environment.handle_exception(exc_info, True)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\jinja2\environment.py", line 780, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "C:\Users\Hassan\AppData\Local\Programs\Python\Python36\lib\site-packages\jinja2\_compat.py", line 37, in reraise
    raise value.with_traceback(tb)
  File "E:\Python\manager\templates\add_account.html", line 1, in top-level template code
    {% extends 'layout.html' %}
  File "E:\Python\manager\templates\layout.html", line 22, in top-level template code
    {% block body %}{% endblock %}
  File "E:\Python\manager\templates\add_account.html", line 10, in block "body"
    {{render_field(form.username, class_='form-control')}}
jinja2.exceptions.UndefinedError: 'render_field' is undefined

Answer 1

你为什么认为有一个render_field函数？有关于此的任何参考资料，您正在阅读哪些文档？无论如何，这应该可以解决问题：

{% extends 'layout.html' %}

{% block body %}
    <br>
    <div class="jumbotron text-center">
       <h1>Add an Account</h1>
       <hr>
       <form action="{{url_for('add_account')}}">
            <div class="form-group">
                {{form.username(class_='form-control')}}
            </div>
            <div class="form-group">
                {{form.email(class_='form-control')}}    
            </div>
            <div class="form-group">
                {{form.password(class_='form-control')}}
            </div>
            <div class="form-group">
                {{form.karma(class_='form-control')}}
            </div>
        </form>
    </div>
{% endblock %}

另请参阅将 css 类添加到 wtform 中的字段。