coercing to Unicode: need string or buffer, NoneType found when rendering in django admin
This error happens when you have a __unicode__
method that is a returning a field that is not entered. Any blank field is None
and Python cannot convert None
, so you get the error.
In your case, the problem most likely is with the PCE
model's __unicode__
method, specifically the field its returning.
You can prevent this by returning a default value:
def __unicode__(self):
return self.some_field or u'None'
This error might occur when you return an object instead of a string in your __unicode__
method. For example:
class Author(models.Model):
. . .
name = models.CharField(...)
class Book(models.Model):
. . .
author = models.ForeignKey(Author, ...)
. . .
def __unicode__(self):
return self.author # <<<<<<<< this causes problems
To avoid this error you can cast the author instance to unicode:
class Book(models.Model):
. . .
def __unicode__(self):
return unicode(self.author) # <<<<<<<< this is OK