我在管理页面上尝试使用“添加”按钮创建新的“研究”实例时出现 str 错误。我可以在shell中创建一个模型实例没问题，但是Admin页面给了我一些问题。我不确定为什么它是非字符串错误，因为 str 正在调用Charfield。
from django.db import models
from django.conf import settings
from account.models import User, UserProfile
# Create your models here.
class StudySite(models.Model):
name = models.CharField(max_length=200, null=True)
address = models.CharField(max_length=200, null=True)
city = models.CharField(max_length=100, null=True)
state = models.CharField(max_length=2, null=True)
def __str__(self):
return self.name
class Study(models.Model):
site = models.ForeignKey(StudySite, blank=True, null=True)
title = models.TextField
shortTitle = models.CharField(max_length=100, null=True)
protocol = models.CharField(max_length=200, blank=True, null=True)
PI = models.ForeignKey('account.UserProfile', limit_choices_to= {'job_title': 'PI'}, related_name='study_PI',
blank=True, null=True)
def __str__(self):
return self.shortTitle
class IRB(models.Model):
name = models.CharField(max_length=100)
url = models.URLField()
任何想法。我在所有搜索中都没有看到（类型方法）错误，所以我很感激一些帮助。谢谢！
Here is the Traceback
Environment:
Request Method: GET
Request URL: http://127.0.0.1:8000/admin/studies/study/add/
Django Version: 1.8.7
Python Version: 3.5.0
Installed Applications:
('django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'studies',
'account')
Installed Middleware:
('django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware',
'django.middleware.security.SecurityMiddleware')
Template error:
In template /Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/contrib/admin/templates/admin/includes/fieldset.html, error at line 19
__str__ returned non-string (type method)
9 : {% for field in line %}
10 : <div{% if not line.fields|length_is:'1' %} class="field-box{% if field.field.name %} field-{{ field.field.name }}{% endif %}{% if not field.is_readonly and field.errors %} errors{% endif %}{% if field.field.is_hidden %} hidden{% endif %}"{% elif field.is_checkbox %} class="checkbox-row"{% endif %}>
11 : {% if not line.fields|length_is:'1' and not field.is_readonly %}{{ field.errors }}{% endif %}
12 : {% if field.is_checkbox %}
13 : {{ field.field }}{{ field.label_tag }}
14 : {% else %}
15 : {{ field.label_tag }}
16 : {% if field.is_readonly %}
17 : <p>{{ field.contents }}</p>
18 : {% else %}
19 : {{ field.field }}
20 : {% endif %}
21 : {% endif %}
22 : {% if field.field.help_text %}
23 : <p class="help">{{ field.field.help_text|safe }}</p>
24 : {% endif %}
25 : </div>
26 : {% endfor %}
27 : </div>
28 : {% endfor %}
29 : </fieldset>
Traceback:
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/core/handlers/base.py" in get_response
164. response = response.render()
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/response.py" in render
158. self.content = self.rendered_content
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/response.py" in rendered_content
135. content = template.render(context, self._request)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/backends/django.py" in render
74. return self.template.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
210. return self._render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in _render
202. return self.nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/loader_tags.py" in render
135. return compiled_parent._render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in _render
202. return self.nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/loader_tags.py" in render
135. return compiled_parent._render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in _render
202. return self.nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/loader_tags.py" in render
65. result = block.nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/loader_tags.py" in render
65. result = block.nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/defaulttags.py" in render
217. nodelist.append(node.render(context))
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/loader_tags.py" in render
159. return template.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
212. return self._render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in _render
202. return self.nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/defaulttags.py" in render
217. nodelist.append(node.render(context))
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/defaulttags.py" in render
217. nodelist.append(node.render(context))
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/defaulttags.py" in render
329. return nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/defaulttags.py" in render
329. return nodelist.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/base.py" in render
905. bit = self.render_node(node, context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render_node
79. return node.render(context)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/template/debug.py" in render
92. output = force_text(output)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/utils/encoding.py" in force_text
90. s = six.text_type(s)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/utils/html.py" in <lambda>
399. klass.__str__ = lambda self: mark_safe(klass_str(self))
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/forms/forms.py" in __str__
537. return self.as_widget()
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/forms/forms.py" in as_widget
593. return force_text(widget.render(name, self.value(), attrs=attrs))
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/contrib/admin/widgets.py" in render
292. 'widget': self.widget.render(name, value, *args, **kwargs),
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/forms/widgets.py" in render
513. options = self.render_options(choices, [value])
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/forms/widgets.py" in render_options
539. for option_value, option_label in chain(self.choices, choices):
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/forms/models.py" in __iter__
1108. yield self.choice(obj)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/forms/models.py" in choice
1115. return (self.field.prepare_value(obj), self.field.label_from_instance(obj))
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/forms/models.py" in label_from_instance
1186. return smart_text(obj)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/utils/encoding.py" in smart_text
56. return force_text(s, encoding, strings_only, errors)
File "/Library/Frameworks/Python.framework/Versions/3.5/lib/python3.5/site-packages/django/utils/encoding.py" in force_text
90. s = six.text_type(s)
Exception Type: TypeError at /admin/studies/study/add/
Exception Value: __str__ returned non-string (type method)