相关疑难解决方法(0)

很长一段时间我都有这个错误,但无法弄清楚:

渲染时捕获TypeError:强制转换为Unicode:需要字符串或缓冲区,找到NoneType

当我尝试在我的一个模型上添加或修改时,它发生在管理员中(显示工作正常)

这是模型:

class PS(models.Model):
    id_ps = models.IntegerField(null=True)
    client = models.ForeignKey(Client, null=True, blank=True)
    nom_du_site = models.CharField(max_length=250)
    rue_livraison = models.TextField(null=True)
    complement_adresse = models.TextField(null=True)
    code_postal_livraison = models.CharField(max_length=50, null=True)
    ville_livraison = models.CharField(max_length=200, null=True)
    pays_livraison = models.CharField(max_length=200, null=True)
    distributeur = models.CharField(max_length=50, null=True)
    tarif = models.CharField(max_length=250, null=True)
    type_tarif = models.CharField(max_length=50, null=True)
    type_installation = models.CharField(max_length=50, null=True)

    def __unicode__(self):
        return self.nom_du_site

    @property
    def pce(self):        
        try:
            return PCE.objects.filter(ps=self)[0]
        except IndexError:
            return
    #    
    def get_pce(self):
        from pce.models import PCE
        return PCE.objects.filter(ps=self).exclude(frequence='6M')
    #
    def get_pce_6m(self):
        from pce.models import PCE …