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：

 1 namespace Client
 2 {
 3     class Program
 4     {
 5         static void Main(string[] args)
 6         {
 7             CalculatorClient client = new CalculatorClient("secure");
 8             double n1 = 5.6;
 9             double n2 = 7.3;
10             double result;
11 
12             result = client.Add(n2, n1);
13             Console.WriteLine("执行加法后的结果为：{0}", result.ToString());
14 
15             result = client.Subtract(n2, n1);
16             Console.WriteLine("执行减法后的结果为：{0}", result.ToString());
17 
18             result = client.Multiply(n1, n2);
19             Console.WriteLine("执行乘法后的结果为：{0}", result.ToString());
20 
21             result = client.Divide(n1, n2);
22             Console.WriteLine("执行除法后的结果为：{0}", result.ToString());
23 
24             //CalculatorSessionClient clientSeesion = new CalculatorSessionClient();
25             //string s = clientSeesion.test("你好我做一个测试！");
26             //string b = clientSeesion.GetServiceDescriptionInfo();
27             //Console.WriteLine(s);
28             //Console.WriteLine(b); 
29           
30             Test();
31 
32         }
33 
34         static void Test()
35         {
36             CalculatorSessionClient wcfClient = new CalculatorSessionClient();
37             try
38             {
39                 using (OperationContextScope scope = new OperationContextScope(wcfClient.InnerChannel))
40                 {
41                     MessageHeader header
42                       = MessageHeader.CreateHeader(
43                       "Service-Bound-CustomHeader",
44                       "http://Microsoft.WCF.Documentation",
45                       "Custom Happy Value."
46                       );
47                     OperationContext.Current.OutgoingMessageHeaders.Add(header);
48 
49                     // Making calls.
50                     Console.WriteLine("Enter the greeting to send: ");
51                     string greeting = Console.ReadLine();
52 
53                     //Console.ReadLine();
54                     header = MessageHeader.CreateHeader(
55                         "Service-Bound-OneWayHeader",
56                         "http://Microsoft.WCF.Documentation",
57                         "Different Happy Value."
58                       );
59                     OperationContext.Current.OutgoingMessageHeaders.Add(header);//TODO:自定义传出消息头的用处？
60 
61                     // One-way
62                     wcfClient.test(greeting);
63                     
64 
65                     // Done with service. 
66                     wcfClient.Close();
67                     Console.WriteLine("Done!");
68                     Console.ReadLine();
69                 }
70             }
71             catch (TimeoutException timeProblem)
72             {
73                 Console.WriteLine("The service operation timed out. " + timeProblem.Message);
74                 Console.ReadLine();
75                 wcfClient.Abort();
76             }
77             catch (CommunicationException commProblem)
78             {
79                 Console.WriteLine("There was a communication problem. " + commProblem.Message);
80                 Console.ReadLine();
81                 wcfClient.Abort();
82             }
83 
84         }
85     }
86 }

2.服务端代码：

  1 namespace Microsoft.ServiceModel.Samples
  2 {
  3     class Program
  4     {
  5         static void Main(string[] args)
  6         {
  7             //创建一个ServiceHost
  8             using (ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService)))
  9             {
 10                 // Open the ServiceHost to create listeners
 11                 serviceHost.Open();
 12                 Console.WriteLine("服务已经开启！");
 13                 Console.WriteLine("按回车键结束服务！");
 14                 Console.WriteLine();
 15                 Console.ReadLine();
 16 
 17                 serviceHost.Close();
 18 
 19             }
 20         }
 21 
 22     }
 23     [ServiceContract]//定义服务协定完成
 24     public interface ICalculator
 25     {
 26         [OperationContract]
 27         double Add(double n1, double n2);
 28         [OperationContract]
 29         double Subtract(double n1, double n2);
 30         [OperationContract]
 31         double Multiply(double n1, double n2);
 32         [OperationContract]
 33         double Divide(double n1, double n2);
 34     }
 35 
 36     [ServiceContract]
 37     public interface ICalculatorSession
 38     {
 39         [OperationContract]
 40         string test(string s);
 41 
 42         [OperationContract]
 43         string GetServiceDescriptionInfo();
 44     }
 45 
 46     public class CalculatorService : ICalculator, ICalculatorSession
 47     {
 48         public double Add(double n1, double n2)
 49         {
 50             return n1 + n2;
 51         }
 52 
 53         public double Subtract(double n1, double n2)
 54         {
 55             return n1 - n2;
 56         }
 57 
 58         public double Multiply(double n1, double n2)
 59         {
 60             return n1 * n2;
 61         }
 62 
 63         public double Divide(double n1, double n2)
 64         {
 65             return n1 / n2;
 66         }
 67 
 68         public string test(string s)
 69         {
 70             Console.WriteLine("Service Said" + s);
 71             WriteHeaders(OperationContext.Current.IncomingMessageHeaders);
 72             return s;
 73         }
 74 
 75         public string GetServiceDescriptionInfo()
 76         {
 77             StringBuilder sb = new StringBuilder();
 78             OperationContext operationContext = OperationContext.Current;
 79             ServiceHost serviceHost = (ServiceHost)operationContext.Host;
 80             ServiceDescription dec = serviceHost.Description;
 81             sb.Append("Base addresses:
");
 82             foreach (Uri url in serviceHost.BaseAddresses)
 83             {
 84                 sb.Append(" " + url + "
");
 85             }
 86             sb.Append("Service endpoint:
");
 87             foreach (ServiceEndpoint endPoint in dec.Endpoints)
 88             {
 89                 sb.Append("Address:" + endPoint.Address + "
");
 90                 sb.Append("Binding:" + endPoint.Binding + "
");
 91                 sb.Append("Contract:" + endPoint.Contract + "
");
 92             }
 93 
 94             return sb.ToString();
 95         }
 96 
 97         private void WriteHeaders(MessageHeaders headers)
 98         {
 99             foreach (MessageHeaderInfo header in headers)
100             {                
101                     Console.WriteLine("	" + header.Actor);
102                     Console.ForegroundColor = ConsoleColor.White;
103                     Console.WriteLine("	" + header.Name);
104                     Console.ForegroundColor = ConsoleColor.Yellow;
105                     Console.WriteLine("	" + header.Namespace);
106                     Console.WriteLine("	" + header.Relay);
107                     if (header.IsReferenceParameter == true)
108                      {
109                          Console.WriteLine("IsReferenceParameter header detected: " + header.ToString());
110                      }                
111             }
112             Console.ResetColor();
113         }
114     }
115 
116 }

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。