public class MyService : IService    {        public Message GetXml(string format)        {            WebOperationContext context = WebOperationContext.Current;            Book b = new Book            {                BookName = "卖女孩的小火柴",                Price = 25.2M,                BarCode = "2811365801"            };            Message msgreturn = null;            // 判断格式            if (format.ToLower() == "xml")            {                msgreturn = context.CreateXmlResponse<Book>(b);            }            else            {                msgreturn = context.CreateJsonResponse<Book>(b);            }            return msgreturn;        }    }

WCF输出JSON