EntityFrameWork异常

Question

/// <summary>        /// Save entity'propertity which is not null        /// </summary>        /// <typeparam name="T"></typeparam>        /// <param name="entity"></param>        public void SetModifyColumnsWithOutNull<T>(T entity) where T : EntityObject        {            ObjectStateEntry stateEntry = null;            bool isPresent = _ctx.ObjectStateManager.TryGetObjectStateEntry(entity, out stateEntry);            if (stateEntry == null)                _ctx.AttachTo(typeof(T).Name, entity);}错误：An object with the same key already exists in the ObjectStateManager. The ObjectStateManager cannot track multiple objects with the same key.说明：我是把上下文放在线程的CallContext里面了，在调用这个方法之前，我查询过该对象，修改之后，调用这个方法进行更新，结果报上述错误。疑问：既然从上下文中获取不到对象状态，那附加对象为何还是出错呢？请大虾们赐教小弟

Answer 1

看错误信息的意思是EF上下文中已经有当前这个实体了，所以不需要AttachTo，你把AttachTo这一行去掉试试