class Ghost(models.Model):
    create = models.DateTimeField(default=timezone.now, help_text='创建时间')
    update = models.DateTimeField(auto_now=True, help_text='修改时间')
    speed = models.IntegerField(default=0, help_text='速度')
    name = models.CharField(max_length=64, help_text='名称')


class InstanceTask(models.Model):
    create = models.DateTimeField(default=timezone.now, help_text='创建时间')
    update = models.DateTimeField(auto_now=True, help_text='修改时间')
    name = models.CharField(max_length=64, help_text='副本名称')

class InstanceTaskMap(models.Model):
    create = models.DateTimeField(default=timezone.now, help_text='创建时间')
    update = models.DateTimeField(auto_now=True, help_text='修改时间')
    name = models.CharField(max_length=64, help_text='地图名称')
    ghosts = models.ManyToManyField(Ghost, help_text='Ghost')
    instance_task = models.ForeignKey(InstanceTask, related_name='instancetask_instancetaskmap', blank=True, null=True,
                                      help_text='副本任务', on_delete=models.SET_NULL)

对于上面的model，如果要在django admin中展示ghosts信息，那么在list_display中直接加入’ghosts’ 会报下面的错误：The value of ‘list_display[1]’ must not be a ManyToManyField.

如果要解决这个问题可以使用下面的代码来展示：

class InstanceTaskMapAdmin(admin.ModelAdmin):
    list_display = ('name', 'instance_task', 'id', 'index', 'get_ghost_name', 'introduction')

    # https://blog.csdn.net/weixin_42134789/article/details/83686664
    def get_ghost_name(self, obj):
        ghost_list = []
        for g in obj.ghosts.all():
            ghost_list.append(g.ghost.name)
        return ','.join(ghost_list)

    get_ghost_name.short_description = "Ghosts" 

如果需要更丰富的信息可以参考上面代码注释中的链接。