通过[OperationContract]从服务器向客户端发送表

I have some problem. I have a simple chat on WCF tech. Chat program consists of server part and client part. I need to pack a table from database and send it to client. But I have no clue how to do that properly, so I decide to do this, and of course, I have a problem: client doesn't recieve the table. What could it be?I have some problem. I have a simple chat on WC