How to: Access WCF Services with One-Way and Request-Reply Contracts

Article
09/15/2021

The following procedures describe how to access a Windows Communication Foundation (WCF) service that defines a one-way contract and a request-reply contract and that does not use the duplex communication pattern.

To define the service

Declare the service contract. The operations that are to be one-way must have IsOneWay set to true within the OperationContractAttribute. The following code declares the IOneWayCalculator contract that has one-way operations for Add, Subtract, Multiply, and Divide. It also defines a request response operation called SayHello.

[ServiceContract(Namespace = "http://Microsoft.ServiceModel.Samples")]  
public interface IOneWayCalculator  
{  
    [OperationContract(IsOneWay = true)]  
    void Add(double n1, double n2);  
    [OperationContract(IsOneWay = true)]  
    void Subtract(double n1, double n2);  
    [OperationContract(IsOneWay = true)]  
    void Multiply(double n1, double n2);  
    [OperationContract(IsOneWay = true)]  
    void Divide(double n1, double n2);  
    [OperationContract]  
    string SayHello(string name);  
}

Implement the service contract. The following code implements the IOnewayCalculator interface.

[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.PerCall)]  
public class CalculatorService : IOneWayCalculator  
{  
    public void Add(double n1, double n2)  
    {  
       double result = n1 + n2;  
       Console.WriteLine("Add({0},{1}) = {2} ", n1, n2, result);  
    }  

    public void Subtract(double n1, double n2)  
    {  
       double result = n1 - n2;  
       Console.WriteLine("Subtract({0},{1}) = {2}", n1, n2, result);  
    }  

    public void Multiply(double n1, double n2)  
    {  
        double result = n1 * n2;  
        Console.WriteLine("Multiply({0},{1}) = {2}", n1, n2, result);  
    }  

    public void Divide(double n1, double n2)  
    {  
        double result = n1 / n2;  
        Console.WriteLine("Divide({0},{1}) = {2}", n1, n2, result);  
    }  

    public string SayHello(string name)  
    {  
        Console.WriteLine("SayHello({0})", name);  
        return "Hello " + name;  
    }  
}

Host the service in a console application. The following code shows how to host the service.

// Host the service within this EXE console application.  
public static void Main()  
{  
   // Define the base address for the service.  
   Uri baseAddress = new Uri("http://localhost:8000/servicemodelsamples/service");  

   // Create a ServiceHost for the CalculatorService type and provide the base address.  
   using (ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService), baseAddress))  
   {  
        // Add an endpoint using the IOneWayCalculator contract and the WSHttpBinding  
        serviceHost.AddServiceEndpoint(typeof(IOneWayCalculator), new WSHttpBinding(), "");  

      // Turn on the metadata behavior, this allows svcutil to get metadata for the service.  
      ServiceMetadataBehavior smb = (ServiceMetadataBehavior) serviceHost.Description.Behaviors.Find<ServiceMetadataBehavior>();  
      if (smb == null)  
      {  
            smb = new ServiceMetadataBehavior();  
            smb.HttpGetEnabled = true;  
            serviceHost.Description.Behaviors.Add(smb);  
      }  

      // Open the ServiceHostBase to create listeners and start listening for messages.  
      serviceHost.Open();  

      // The service can now be accessed.  
      Console.WriteLine("The service is ready.");  
      Console.WriteLine("Press <ENTER> to terminate service.");  
      Console.WriteLine();  
      Console.ReadLine();  
    }  
}

To access the service

Run the ServiceModel Metadata Utility Tool (Svcutil.exe) using the metadata exchange endpoint address to create the client class for the service using the following command line: Svcutil http://localhost:8000/Service The ServiceModel Metadata Utility Tool (Svcutil.exe) generates a set of interfaces and classes, as shown in the following sample code.

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]  
[System.ServiceModel.ServiceContractAttribute(Namespace="http://Microsoft.ServiceModel.Samples", ConfigurationName="IOneWayCalculator")]  
public interface IOneWayCalculator  
{  

    [System.ServiceModel.OperationContractAttribute(IsOneWay=true, Action="http://Microsoft.ServiceModel.Samples/IOneWayCalculator/Add")]  
    void Add(double n1, double n2);  

    [System.ServiceModel.OperationContractAttribute(IsOneWay=true, Action="http://Microsoft.ServiceModel.Samples/IOneWayCalculator/Subtract")]  
    void Subtract(double n1, double n2);  

    [System.ServiceModel.OperationContractAttribute(IsOneWay=true, Action="http://Microsoft.ServiceModel.Samples/IOneWayCalculator/Multiply")]  
    void Multiply(double n1, double n2);  

    [System.ServiceModel.OperationContractAttribute(IsOneWay=true, Action="http://Microsoft.ServiceModel.Samples/IOneWayCalculator/Divide")]  
    void Divide(double n1, double n2);  

    [System.ServiceModel.OperationContractAttribute(Action="http://Microsoft.ServiceModel.Samples/IOneWayCalculator/SayHello", ReplyAction="http://Microsoft.ServiceModel.Samples/IOneWayCalculator/SayHelloResponse")]  
    string SayHello(string name);  
}  

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]  
public interface IOneWayCalculatorChannel : IOneWayCalculator, System.ServiceModel.IClientChannel  
{  
}  

[System.Diagnostics.DebuggerStepThroughAttribute()]  
[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]  
public partial class OneWayCalculatorClient : System.ServiceModel.ClientBase<IOneWayCalculator>, IOneWayCalculator  
{  

    public OneWayCalculatorClient()  
    {  
    }  

    public OneWayCalculatorClient(string endpointConfigurationName) :
            base(endpointConfigurationName)  
    {  
    }  

    public OneWayCalculatorClient(string endpointConfigurationName, string remoteAddress) :
            base(endpointConfigurationName, remoteAddress)  
    {  
    }  

    public OneWayCalculatorClient(string endpointConfigurationName, System.ServiceModel.EndpointAddress remoteAddress) :
            base(endpointConfigurationName, remoteAddress)  
    {  
    }  

    public OneWayCalculatorClient(System.ServiceModel.Channels.Binding binding, System.ServiceModel.EndpointAddress remoteAddress) :
            base(binding, remoteAddress)  
    {  
    }  

    public void Add(double n1, double n2)  
    {  
        base.Channel.Add(n1, n2);  
    }  

    public void Subtract(double n1, double n2)  
    {  
        base.Channel.Subtract(n1, n2);  
    }  

    public void Multiply(double n1, double n2)  
    {  
        base.Channel.Multiply(n1, n2);  
    }  

    public void Divide(double n1, double n2)  
    {  
        base.Channel.Divide(n1, n2);  
    }  

    public string SayHello(string name)  
    {  
        return base.Channel.SayHello(name);  
    }  
}

Notice in the IOneWayCalculator interface that the one-way service operations have the IsOneWay attribute set to true and the request-reply service operation has the attribute set to the default value, false. Also notice the OneWayCalculatorClient class. This is the class that you will use to call the service.

Create the client object.

// Create a client  
WSHttpBinding binding = new WSHttpBinding();  
EndpointAddress epAddress = new EndpointAddress("http://localhost:8000/servicemodelsamples/service");  
OneWayCalculatorClient client = new OneWayCalculatorClient(binding, epAddress);

Call service operations.

// Call the Add service operation.  
double value1 = 100.00D;  
double value2 = 15.99D;  
client.Add(value1, value2);  
Console.WriteLine("Add({0},{1})", value1, value2);  

// Call the Subtract service operation.  
value1 = 145.00D;  
value2 = 76.54D;  
client.Subtract(value1, value2);  
Console.WriteLine("Subtract({0},{1})", value1, value2);  

// Call the Multiply service operation.  
value1 = 9.00D;  
value2 = 81.25D;  
client.Multiply(value1, value2);  
Console.WriteLine("Multiply({0},{1})", value1, value2);  

// Call the Divide service operation.  
value1 = 22.00D;  
value2 = 7.00D;  
client.Divide(value1, value2);  
Console.WriteLine("Divide({0},{1})", value1, value2);  

// Call the SayHello service operation  
string name = "World";  
string response = client.SayHello(name);  
Console.WriteLine("SayHello([0])", name);  
Console.WriteLine("SayHello() returned: " + response);

Close the client to close connections and clean up resources.

//Closing the client gracefully closes the connection and cleans up resources  
client.Close();

Example

The following is a complete listing of the code used in this topic.

// Service.cs  
using System;  
using System.Configuration;  
using System.ServiceModel;  
using System.ServiceModel.Description;  
  
namespace Microsoft.ServiceModel.Samples  
{  
    // Define a service contract.
    [ServiceContract(Namespace = "http://Microsoft.ServiceModel.Samples")]  
    public interface IOneWayCalculator  
    {  
        [OperationContract(IsOneWay = true)]  
        void Add(double n1, double n2);  
        [OperationContract(IsOneWay = true)]  
        void Subtract(double n1, double n2);  
        [OperationContract(IsOneWay = true)]  
        void Multiply(double n1, double n2);  
        [OperationContract(IsOneWay = true)]  
        void Divide(double n1, double n2);  
        [OperationContract]  
        string SayHello(string name);  
    }  
  
    // Service class which implements the service contract.  
    // Added code to write output to the console window  
    [ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple, InstanceContextMode = InstanceContextMode.PerCall)]  
    public class CalculatorService : IOneWayCalculator  
    {  
        public void Add(double n1, double n2)  
        {  
            double result = n1 + n2;  
            Console.WriteLine("Add({0},{1}) = {2} ", n1, n2, result);  
        }  
  
        public void Subtract(double n1, double n2)  
        {  
            double result = n1 - n2;  
            Console.WriteLine("Subtract({0},{1}) = {2}", n1, n2, result);  
        }  
  
        public void Multiply(double n1, double n2)  
        {  
            double result = n1 * n2;  
            Console.WriteLine("Multiply({0},{1}) = {2}", n1, n2, result);  
        }  
  
        public void Divide(double n1, double n2)  
        {  
            double result = n1 / n2;  
            Console.WriteLine("Divide({0},{1}) = {2}", n1, n2, result);  
        }  
  
        public string SayHello(string name)  
        {  
            Console.WriteLine("SayHello({0})", name);  
            return "Hello " + name;  
        }  
  
        // Host the service within this EXE console application.  
        public static void Main()  
        {  
            // Define the base address for the service.  
            Uri baseAddress = new Uri("http://localhost:8000/servicemodelsamples/service");  
  
            // Create a ServiceHost for the CalculatorService type and provide the base address.  
            using (ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService), baseAddress))  
            {  
                // Add an endpoint using the IOneWayCalculator contract and the WSHttpBinding  
                serviceHost.AddServiceEndpoint(typeof(IOneWayCalculator), new WSHttpBinding(), "");  
  
                // Turn on the metadata behavior, this allows svcutil to get metadata for the service.  
                ServiceMetadataBehavior smb = (ServiceMetadataBehavior) serviceHost.Description.Behaviors.Find<ServiceMetadataBehavior>();  
                if (smb == null)  
                {  
                    smb = new ServiceMetadataBehavior();  
                    smb.HttpGetEnabled = true;  
                    serviceHost.Description.Behaviors.Add(smb);  
                }  
  
                // Open the ServiceHostBase to create listeners and start listening for messages.  
                serviceHost.Open();  
  
                // The service can now be accessed.  
                Console.WriteLine("The service is ready.");  
                Console.WriteLine("Press <ENTER> to terminate service.");  
                Console.WriteLine();  
                Console.ReadLine();  
            }  
        }  
    }  
}

// client.cs  
using System;  
using System.ServiceModel;  
  
namespace Microsoft.ServiceModel.Samples  
{  
    //The service contract is defined in generatedClient.cs, generated from the service by the svcutil tool.  
  
    //Client implementation code.  
    class Client  
    {  
        static void Main()  
        {  
            // Create a client  
            WSHttpBinding binding = new WSHttpBinding();  
            EndpointAddress epAddress = new EndpointAddress("http://localhost:8000/servicemodelsamples/service");  
            OneWayCalculatorClient client = new OneWayCalculatorClient(binding, epAddress);  
  
            // Call the Add service operation.  
            double value1 = 100.00D;  
            double value2 = 15.99D;  
            client.Add(value1, value2);  
            Console.WriteLine("Add({0},{1})", value1, value2);  
  
            // Call the Subtract service operation.  
            value1 = 145.00D;  
            value2 = 76.54D;  
            client.Subtract(value1, value2);  
            Console.WriteLine("Subtract({0},{1})", value1, value2);  
  
            // Call the Multiply service operation.  
            value1 = 9.00D;  
            value2 = 81.25D;  
            client.Multiply(value1, value2);  
            Console.WriteLine("Multiply({0},{1})", value1, value2);  
  
            // Call the Divide service operation.  
            value1 = 22.00D;  
            value2 = 7.00D;  
            client.Divide(value1, value2);  
            Console.WriteLine("Divide({0},{1})", value1, value2);  
  
            // Call the SayHello service operation  
            string name = "World";  
            string response = client.SayHello(name);  
            Console.WriteLine("SayHello([0])", name);  
            Console.WriteLine("SayHello() returned: " + response);  
            //Closing the client gracefully closes the connection and cleans up resources  
            client.Close();  
  
        }  
    }  
}

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How to: Access WCF Services with One-Way and Request-Reply Contracts

To define the service

To access the service

Example

See also

Additional resources