wcf之OperationContextScope

作用：使用消息头向服务发送额外的信息。

1.客户端代码如下：

   

namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            CalculatorClient client = new CalculatorClient("secure");
            double n1 = 5.6;
            double n2 = 7.3;
            double result;

            result = client.Add(n2, n1);
            Console.WriteLine("执行加法后的结果为：{0}", result.ToString());

            result = client.Subtract(n2, n1);
            Console.WriteLine("执行减法后的结果为：{0}", result.ToString());

            result = client.Multiply(n1, n2);
            Console.WriteLine("执行乘法后的结果为：{0}", result.ToString());

            result = client.Divide(n1, n2);
            Console.WriteLine("执行除法后的结果为：{0}", result.ToString());

            //CalculatorSessionClient clientSeesion = new CalculatorSessionClient();
            //string s = clientSeesion.test("你好我做一个测试！");
            //string b = clientSeesion.GetServiceDescriptionInfo();
            //Console.WriteLine(s);
            //Console.WriteLine(b); 
          
            Test();

        }

        static void Test()
        {
            CalculatorSessionClient wcfClient = new CalculatorSessionClient();
            try
            {
                using (OperationContextScope scope = new OperationContextScope(wcfClient.InnerChannel))
                {
                    MessageHeader header
                      = MessageHeader.CreateHeader(
                      "Service-Bound-CustomHeader",
                      "http://Microsoft.WCF.Documentation",
                      "Custom Happy Value."
                      );
                    OperationContext.Current.OutgoingMessageHeaders.Add(header);

                    // Making calls.
                    Console.WriteLine("Enter the greeting to send: ");
                    string greeting = Console.ReadLine();

                    //Console.ReadLine();
                    header = MessageHeader.CreateHeader(
                        "Service-Bound-OneWayHeader",
                        "http://Microsoft.WCF.Documentation",
                        "Different Happy Value."
                      );
                    OperationContext.Current.OutgoingMessageHeaders.Add(header);//TODO:自定义传出消息头的用处？

                    // One-way
                    wcfClient.test(greeting);
                    

                    // Done with service. 
                    wcfClient.Close();
                    Console.WriteLine("Done!");
                    Console.ReadLine();
                }
            }
            catch (TimeoutException timeProblem)
            {
                Console.WriteLine("The service operation timed out. " + timeProblem.Message);
                Console.ReadLine();
                wcfClient.Abort();
            }
            catch (CommunicationException commProblem)
            {
                Console.WriteLine("There was a communication problem. " + commProblem.Message);
                Console.ReadLine();
                wcfClient.Abort();
            }

        }
    }
}

2.服务端代码：

namespace Microsoft.ServiceModel.Samples
{
    class Program
    {
        static void Main(string[] args)
        {
            //创建一个ServiceHost
            using (ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService)))
            {
                // Open the ServiceHost to create listeners
                serviceHost.Open();
                Console.WriteLine("服务已经开启！");
                Console.WriteLine("按回车键结束服务！");
                Console.WriteLine();
                Console.ReadLine();

                serviceHost.Close();

            }
        }

    }
    [ServiceContract]//定义服务协定完成
    public interface ICalculator
    {
        [OperationContract]
        double Add(double n1, double n2);
        [OperationContract]
        double Subtract(double n1, double n2);
        [OperationContract]
        double Multiply(double n1, double n2);
        [OperationContract]
        double Divide(double n1, double n2);
    }

    [ServiceContract]
    public interface ICalculatorSession
    {
        [OperationContract]
        string test(string s);

        [OperationContract]
        string GetServiceDescriptionInfo();
    }

    public class CalculatorService : ICalculator, ICalculatorSession
    {
        public double Add(double n1, double n2)
        {
            return n1 + n2;
        }

        public double Subtract(double n1, double n2)
        {
            return n1 - n2;
        }

        public double Multiply(double n1, double n2)
        {
            return n1 * n2;
        }

        public double Divide(double n1, double n2)
        {
            return n1 / n2;
        }

        public string test(string s)
        {
            Console.WriteLine("Service Said" + s);
            WriteHeaders(OperationContext.Current.IncomingMessageHeaders);
            return s;
        }

        public string GetServiceDescriptionInfo()
        {
            StringBuilder sb = new StringBuilder();
            OperationContext operationContext = OperationContext.Current;
            ServiceHost serviceHost = (ServiceHost)operationContext.Host;
            ServiceDescription dec = serviceHost.Description;
            sb.Append("Base addresses:
");
            foreach (Uri url in serviceHost.BaseAddresses)
            {
                sb.Append(" " + url + "
");
            }
            sb.Append("Service endpoint:
");
            foreach (ServiceEndpoint endPoint in dec.Endpoints)
            {
                sb.Append("Address:" + endPoint.Address + "
");
                sb.Append("Binding:" + endPoint.Binding + "
");
                sb.Append("Contract:" + endPoint.Contract + "
");
            }

            return sb.ToString();
        }

        private void WriteHeaders(MessageHeaders headers)
        {
            foreach (MessageHeaderInfo header in headers)
            {                
                    Console.WriteLine("	" + header.Actor);
                    Console.ForegroundColor = ConsoleColor.White;
                    Console.WriteLine("	" + header.Name);
                    Console.ForegroundColor = ConsoleColor.Yellow;
                    Console.WriteLine("	" + header.Namespace);
                    Console.WriteLine("	" + header.Relay);
                    if (header.IsReferenceParameter == true)
                     {
                         Console.WriteLine("IsReferenceParameter header detected: " + header.ToString());
                     }                
            }
            Console.ResetColor();
        }
    }

}

这个实例演示的是客户端通过OutgoingMessageHeaders添加了一些信息，然后服务端通过IncomingMessageHeaders

附：(也许你会有疑问，事情都是OperationContext做的，要OperationContextScope 干什么：个人理解OperationContextScope 类似于数据库连接对象类，wcfClient.InnerChannel就好像是连接字符串，告诉要连接到哪去，整个OperationContextScope 块就像是数据库中的当期连接，信息头就好像是sql语句，出了OperationContextScope 块范围就好数据库断开了连接，进行其他操作要重新连接，OperationContext 就好像是Command对象执行一些操作)

OperationContextScope 对象建立了当前操作上下文之后，可以使用 OperationContext 执行以下操作：

• 访问和修改传入和传出消息头和其他属性。

• 访问运行库，包括调度程序、主机、信道和扩展。

• 访问其他类型的上下文，如安全、实例和请求上下文。

• 访问与 OperationContext 对象关联的信道，或（如果信道实现System.ServiceModel.Channels.ISession）访问关联信道的会话标识符。

创建了 OperationContextScope 后，将存储当前的 OperationContext，并且新的 OperationContext 由Current 属性所返回。释放 OperationContextScope 后，将还原原始 OperationContext。