1、引用：
using System.ServiceModel;
 using System.ServiceModel.Description;2、申明接口
///这是接口
 [ServiceContract(Namespace = "http://Microsoft.ServiceModel.Samples")]

 public interface MyJK

 {

 [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);

}

3、实现接口
    //实现契约和接口
     public class AABB : MyJK
     {
         public double Add(double n1, double n2)
         {
             double result = n1 + n2;
             Console.WriteLine("Received Add({0},{1})", n1, n2);
             Console.WriteLine("Return: {0}", result);
             return result;
         }


         public double Subtract(double n1, double n2)
         {
             double result = n1 - n2;
             Console.WriteLine("Received Subtract({0},{1})", n1, n2);
             Console.WriteLine("Return: {0}", result);
             return result;
         }


         public double Multiply(double n1, double n2)
         {
             double result = n1 * n2;
             Console.WriteLine("Received Multiply({0},{1})", n1, n2);
             Console.WriteLine("Return: {0}", result);
             return result;
         }


         public double Divide(double n1, double n2)
         {
             double result = n1 / n2;
             Console.WriteLine("Received Divide({0},{1})", n1, n2);
             Console.WriteLine("Return: {0}", result);
             return result;
         }
     }4、定义服务、启动服务
         Uri baseAddress = new Uri("http://localhost:8989/aaa/");    //随便写
          ServiceHost serviceHost = new ServiceHost(typeof(AABB), baseAddress);         serviceHost.AddServiceEndpoint(typeof(MyJK), new WSHttpBinding(), "BBCCDD");
          ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
          smb.HttpGetEnabled = true;
          serviceHost.Description.Behaviors.Add(smb);         serviceHost.Open();