/// <summary>
        /// 发送消息
        /// </summary>
        public void DoSend(params string[] receiverIds)
        {
            if (receiverIds == null || receiverIds.Length <= 0)
            {
                if (!String.IsNullOrEmpty(this.ReceiverId))
                {
                    receiverIds = this.ReceiverId.Split(',', ';');
                }
            }

            if (receiverIds != null && receiverIds.Length > 0)
            {
                SysUser[] users = SysUser.FindAllByPrimaryKeys(receiverIds);

                foreach (SysUser tuser in users)
                {
                    SysMessage msg = new SysMessage();
                    msg.SenderId       = this.SenderId;
                    msg.SenderName     = this.SenderName;
                    msg.Title          = this.Title;
                    msg.MessageContent = this.MessageContent;
                    msg.Attachment     = this.Attachment;
                    msg.SendTime       = DateTime.Now;
                    msg.ReceiverId     = tuser.UserID;
                    msg.ReceiverName   = tuser.Name;

                    msg.DoCreate();
                }
            }
        }
        /// <summary>
        /// 消息发送操作
        /// </summary>
        public static void Send(string senderId, string title, string content, string attachment, params string[] receiverIds)
        {
            if (receiverIds != null && receiverIds.Length > 0)
            {
                SysUser sender = SysUser.Find(senderId);

                SysMessage msg = new SysMessage();
                msg.SenderId       = sender.UserID;
                msg.SenderName     = sender.Name;
                msg.Title          = title;
                msg.MessageContent = content;
                msg.Attachment     = attachment;

                msg.DoSend(receiverIds);
            }
            else
            {
                throw new MessageException("接收人不能为空。");
            }
        }