尝试渲染自定义窗体小部件在我的模板标记中不起作用

Question

我有一个模板标记，可以为我呈现一些自定义表单小部件。当我升级到Django 1.8时，它停止了工作。我试图弄清楚如何解决这个问题。

最终在表单字段的模板中呈现的是：

<project.appname.widgets.RadioFeedbackInput object at 0x10a8e5d50>

下面，在模板标签中，我认为问题出在render_to_string中。有什么建议吗？

这是我的模板标签：

from django import template
from django.template import loader, RequestContext
from django.template.defaultfilters import slugify

register = template.Library()

@register.tag
def render_form(parser, token):
    """Renders dynamic form accordingly"""

    bits = token.split_contents()
    if len(bits) < 2:
        raise template.TemplateSyntaxError("%r tag takes at least one argument" % bits[0])

    form = bits[1]
    args = {}

    # Parse extra "asvar" if given
    if len(bits) > 2:
        biter = iter(bits[2:])
        for bit in biter:
            if bit == "as":
                args["asvar"] = biter.next()
            else:
                raise template.TemplateSyntaxError("%r tag got an unknown argument: %r" % (bits[0], bit))

    return RenderFormNode(form, **args)


class RenderFormNode(template.Node):
    def __init__(self, form, asvar=None):
        self.form = form
        self.asvar = asvar

    def render(self, context):
        context = context or {}
        form = template.Variable(self.form).resolve(context)
        try:
            request = template.Variable('request').resolve(context)
        except template.VariableDoesNotExist:
            raise template.VariableDoesNotExist("The `render_form` template tag requires that the request context processor be enabled.")

        # The question type is used to build out the template type.
        template_path_context = {
            'type': slugify(form.template_type)
        }

        template_list = [
            'appname/question_types/%(type)s/form.html' % template_path_context,
            'appname/question_types/%(type)s.html' % template_path_context,
            'appname/%(type)s/form.html' % template_path_context,
            'appname/form.html' % template_path_context
        ]

        # Renders form, and saves to self.asvar if requested
        context.update({'form': form})
        rendered = loader.render_to_string(
            template_list,
            context
        )
        if self.asvar:
            context[self.asvar] = rendered
            return ''
        return rendered

这里是小部件模板：

<div class="radio-button-block">
    {% for fields in form %}
        {% if forloop.first %}
            <label>{{ fields.label|linebreaks }}</label>
            <div class="radio-button">
        {% endif %}
        {% for field in fields %}
            <div class="field">
                {{ field }}
                {% if field.errors %}
                    {% for error in field.errors %}
                        <div class="ui negative message">
                            {{ error }}
                        </div>
                    {% endfor %}
                {% endif %}
                {% if field.choice_feedback %}
                    <div class="feedback">
                        {{ field.choice_feedback|linebreaks }}
                        <a class="close-feedback ss-icon">close</a>
                    </div>
                {% endif %}
            </div>
        {% endfor %}
    {% endfor %}
    </div>
</div>