django python无法连接＆＃39; str＆＃39;和＆＃39; __代理__＆＃39;对象

Question

我在Django应用程序中有forms.py。

from django import forms
from django.core.urlresolvers import reverse_lazy

class ComposeMessageForm(forms.Form):
ccc = reverse_lazy('user_api')
st = 'customSelectize:u_r,modelUrl:"'+ reverse_lazy('user_api') +'", choiceField:"username"'
user_receivers = forms.ModelMultipleChoiceField(
    queryset=User.objects.all(),
    required=False,
    widget=forms.SelectMultiple(
        attrs={
            'data-bind': st,
            'placeholder': 'Select USERS'}))

当我运行它时，我得到了

TypeError at /message/compose/

cannot concatenate 'str' and '__proxy__' objects

如何做到这一点？我不知道__proxy__对象是什么。

urls.py是：

from django.conf.urls import patterns, include, url
from rest_framework.urlpatterns import format_suffix_patterns
from django.contrib import admin
from msgin import views

urlpatterns = patterns('',
                   url(r'^$', 'ms.views.home', name='home'),
                   url(r'^message/', include('msgin.urls')),
                   url(r'^admin/', include(admin.site.urls)),
                   url(r'^msgs/$', views.MessageList.as_view()),
                   url(r'^msgs/(?P<pk>[0-9]+)/$',
                       views.MessageDetail.as_view()),
                   url(r'^users/$', views.UserList.as_view(),
                       name='user_api'),
                   url(r'^users/(?P<pk>[0-9]+)/$',
                       views.UserDetail.as_view()),
                   url(r'^groups/$', views.GroupList.as_view(),
                       name='groups_api'),
                   url(r'^groups/(?P<pk>[0-9]+)/$',
                       views.GroupDetail.as_view()),
                   )

Answer 1

把它放在 str() 里面

from django.utils.translation import ugettext_lazy as _
str(self.price) + " " + str(_("USD"))

Answer 2

代理 url是稍后解析的网址，而不是在调用reverse_lazy() func时解析的网址。对于这个具体案例，您可以使用简单的reverse()函数而不是惰性函数。

但是如果你想将代理网址强制转换为字符串时使用reverse_lazy()：

st = 'customSelectize:u_r,modelUrl:"'+ str(reverse_lazy('user_api')) +'", choiceField:"username"'

或使用字符串格式：

st = 'customSelectize:u_r,modelUrl:"%s", choiceField:"username"' % reverse_lazy('user_api')

Answer 3

在类定义中使用reverse_lazy没有任何好处，因为不能＆＃34;懒惰＆＃34;

你有两个选择

1）使用reverse

2）将您的代码更改为

class ComposeMessageForm(forms.Form):

    user_receivers = forms.ModelMultipleChoiceField(queryset=User.objects.all(),
                                                    required=False)

    def __init__(self, *args, **kwargs):
        super(ComposeMessageForm, self).__init__(*args, **kwargs)
        st = 'customSelectize:u_r,modelUrl:"%s", choiceField:"username"' % reverse_lazy('user_api')
        self.fields['user_receivers'].widget=forms.SelectMultiple(attrs={'data-bind': st, 
                                                                         'placeholder': 'Select USERS'})