c# – 调用服务时出现InvalidOperationException

The contract type HelloIndigo.Service is not attributed with
ServiceContractAttribute. In order to define a valid contract,the
specified type (either contract interface or service class) must be
attributed with ServiceContractAttribute.

我构建了一个库类,并在控制台应用程序中引用了该类.

图书馆类：

namespace HelloIndigo
{
  public class Service : IHelloIndigoService
  {
      public string HelloIndigo()
      {
        return "Hello Indigo";
      }
  }

  [ServiceContract(Namespace = "http://www.thatindigogirl.com/samples/2006/06")]
  interface IHelloIndigoService
  {
    [OperationContract]
    string HelloIndigo();
  }
}

控制台应用程序：

namespace Host
{
  class Program
  {
    static void Main(string[] args)
    {
      using (ServiceHost host = new ServiceHost(typeof(HelloIndigo.Service),new Uri("http://localhost:8000/HelloIndigo")))
      {
        host.AddServiceEndpoint(typeof(HelloIndigo.Service),new BasicHttpBinding(),"Service");
        host.Open();
        Console.WriteLine("Press enter to terminate the host service");
        Console.ReadLine();
      }
    }
  }
}