Beginner's Guide to Windows Communication Foundation

Building your first WCF Application

1. Open Visual Studio 2005 and create a new class library project called DemoInterfaces.
2. In Solution Explorer, right-click on references and add a .NET reference to System.ServiceModel.
3. Add new interface to the project named "ICustomer.cs"
4. Copy and paste below specified interface into ICustomer.cs
   
   1. using System.ServiceModel;
   2. namespace DemoInterfaces
   3. {
   4. [ServiceContract]
   5. public interface ICustomer
   6. {
   7. [OperationContract]
   8. string SayHello(string name);
   9. }
   10. }
5. Build the project, which will create DemoInterfaces.DLL.

System.ServiceModel is the primary DLL in the .NET 3.0 Framework for WCF. Make sure to add a .NET reference to System.ServiceModel any time you write code using the WCF object model.

[ServiceContract] attribute can be applied either to the interface or to the class directly. [ServiceContract] attribute is just an indication for the WCF runtime that this CLR type can be hosted as a WCF service. Without this attribute a type cannot be hosted as a WCF service.

[OperationContract] attribute can be applied either to the method declarations in the interface or to definitions in the class directly[OperationContract] attribute is just an indication for the WCF runtime that this method can be exposed to the outside word as part of the service. Consider this attribute as similar to [WebMethod] attribute, without which a method cannot be exposed to the outside world.

1. Create a new class library project called DemoCustomerBz.
2. In Solution Explorer, right-click on references and add a .NET reference to System.ServiceModel.
3. In Solution Explorer, right-click on references and add a .NET reference to the DemoInterfaces.DLL that you created when you built the interface project in the previous step.
4. Add a new class to the project named "Customer.cs"
5. Copy and paste below specified code into "Customer.cs"
   
   1. using DemoInterfaces;
   2. namespace DemoCustomerBz
   3. {
   4. public class Customer:ICustomer
   5. {
   6. #region ICustomer Members
   7. public string SayHello(string name)
   8. {
   9. return "Hello " + name + "!...";
   10. }
   11. #endregion
   12. }
   13. }
6. Build the project, which will create DemoCustomerBz.DLL

Remember, all the types which are marked with [ServiceContract] are known as services. These services can not be exposed on its own. We need a Host process to host these services.

1. Create a new console application project called DemoCustomerHost.
2. In Solution Explorer, right-click on references and add a .NET reference to System.ServiceModel.
3. In Solution Explorer, right-click on references and add a .NET reference to the previously created libraries: DemoInterfaces.DLL and DemoCustomerBz.Dll.
4. Double click on "program.cs" to open the file
5. Copy and paste below specified code into "program.cs"
   
   1. using System;
   2. using System.ServiceModel;
   3. using DemoInterfaces;
   4. using DemoCustomerBz;
   5. namespace DemoCustomerHost
   6. {
   7. class Program
   8. {
   9. static void Main(string[] args)
   10. {
   11. using (ServiceHost host = new ServiceHost(
   12. typeof(Customer),
   13. new Uri("http://localhost:8000/Customer")))
   14. {
   15. host.AddServiceEndpoint(
   16. typeof(ICustomer), // Contract
   17. new BasicHttpBinding(), // Binding
   18. "CustomerService"); // Address
   19. host.Open();
   20. Console.WriteLine ("Service is up and running.");
   21. Console.WriteLine("Press <Enter> to stop service...");
   22. Console.ReadLine(); host.Close();
   23. }
   24. }
   25. }
   26. }
6. Build the project, which will create DemoCustomerHost.Exe

1. Create a new console application project called DemoClient.
2. In Solution Explorer, right-click on references and add a .NET reference to System.ServiceModel.
3. Client and Service need a contract to establish communication. To add the contract, in Solution Explorer, right-click on references and add a .NET reference to the previously created library: DemoInterfaces.DLL
   
   

   Client and Service need to share only Contract, Not Code. So, we need not to add reference to DemoCustomerBz.dl.

   
   
4. Double click on "program.cs" to open the file
5. Copy and paste below specified code into "program.cs"
   

   1. using System;
   2. using DemoInterfaces;
   3. using System.ServiceModel;
   4. namespace DemoClient
   5. {
   6. class Program
   7. {
   8. static void Main(string[] args)
   9. {
   10. ICustomer proxy = ChannelFactory<ICustomer>.
   11. CreateChannel(
   12. new BasicHttpBinding(),
   13. new EndpointAddress("http://localhost:8000/Customer/CustomerService"));
   14. string result = proxy.SayHello("Test Client");
   15. Console.WriteLine("Server says : " + result);
   16. Console.WriteLine("Press <Enter> to stop client...");
   17. Console.ReadLine();
   18. }
   19. }
   20. }
6. Compile the solution and run the host project first, followed by the client project.
7. The client console output will be displayed as:
   
   
   
   The above code uses ChannelFactory to creat a new channel to invoke the service. This strongly typed channel reference acts as a proxy. The code also initializes an EndpointAddress with the correct address and binding expected by the service endpoint.

1. Open the already created project DemoCustomerHost.
2. Double click on "program.cs" to open the file
3. Copy and paste below specified code into "program.cs:
   
   1. using System;
   2. using System.ServiceModel;
   3. using DemoInterfaces;
   4. using DemoCustomerBz;
   5. namespace DemoCustomerHost
   6. {
   7. class Program
   8. {
   9. static void Main(string[] args)
   10. {
   11. using (ServiceHost host = new ServiceHost(typeof(Customer)))
   12. {
   13. // URI and endpoint information will be fetched from app.config
   14. host.Open();
   15. Console.WriteLine("Service is up and running.");
   16. Console.WriteLine("Press <Enter> to stop service...");
   17. Console.ReadLine();
   18. host.Close();
   19. }
   20. }
   21. }
   22. }
   The above code initializes a ServiceHost instance specifying the service type and no endpoint information have been specified in the code. When the required information is not available in the code, WCF runtime looks for the information in the application configuration file and adds endpoint information on the fly, to the service.
4. Add new file to the application named "app.config"
5. Copy and past below specified text into "app.config"
   1. <?xml version="1.0" encoding="utf-8" ?>
   2. <configuration>
   3. <system.serviceModel>
   4. <services>
   5. <service name="DemoCustomerBz.Customer">
   6. <endpoint address="CustomerService" binding="basicHttpBinding" bindingConfiguration="" name="basicHttp" contract="DemoInterfaces.ICustomer" />
   7. <host>
   8. <baseAddresses>
   9. <add baseAddress="http://localhost:8000/Customer" />
   10. </baseAddresses>
   11. </host>
   12. </service>
   13. </services>
   14. </system.serviceModel>
   15. </configuration>

   In the above config file, we are adding configuration entry for one endpoint which is accessed over basicHttpBinding at http://localhost:8000/Customer/CustomerService. We can add any number of end points to the service by adding multiple endpoint tags to the app.config.
6. Build the project, which will create DemoCustomerHost.Exe

ProxyGeneration

1. Open the project DemoCustomerHost which uses app.config file
2. Double click on the file "app.config" to open
3. Copy and paste below specified text into "app.config"
   1. <?xml version="1.0" encoding="utf-8" ?>
   2. <configuration>
   3. <system.serviceModel>
   4. <behaviors>
   5. <serviceBehaviors>
   6. <behavior name="metadataBehavior">
   7. <serviceMetadata httpGetEnabled="true" />
   8. </behavior>
   9. </serviceBehaviors>
   10. </behaviors>
   11. <services>
   12. <service behaviorConfiguration="metadataBehavior" name="DemoCustomerBz.Customer">
   13. <endpoint address="CustomerService" binding="basicHttpBinding" bindingConfiguration="" name="basicHttp" contract="DemoInterfaces.ICustomer" />
   14. <endpoint binding="mexHttpBinding" bindingConfiguration="" name="metadataExchange" contract="IMetadataExchange" />
   15. <host>
   16. <baseAddresses>
   17. <add baseAddress="http://localhost:8000/Customer" />
   18. </baseAddresses>
   19. </host>
   20. </service>
   21. </services>
   22. </system.serviceModel>
   23. </configuration>

   In the above config file, we have added new endpoint to expose metadata for the clients. To expose metadata, we must enable httpGet, this is been done using serviceBehaviors configuration entry.
4. Build the project, which will create DemoCustomerHost.Exe

1. Create a new console application project called DemoClient.
2. In Solution Explorer, right-click on references and add a .NET reference to System.ServiceModel.
3. Make sure that the host application created in the previous section is running, to generate proxy
   
   
   
4. Right click on the project and select "Add service reference…"
   
   
   
5. Provide URI for the service , specify namespace as "CustomerProxy and click on "Add" button
   
   
   
6. Two files app.config and CustomerProxy will be generated and added automatically to the project.
   
   
   
7. Auto generated app.config in the client app, looks as given below:
   
   1. <?xml version="1.0" encoding="utf-8" ?>
   2. <configuration>
   3. <system.serviceModel>
   4. <bindings>
   5. <basicHttpBinding>
   6. <binding name="basicHttp" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true">
   7. <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384" />
   8. <security mode="None">
   9. <transport clientCredentialType="None" proxyCredentialType="None" realm="" />
   10. <message clientCredentialType="UserName" algorithmSuite="Default" />
   11. </security>
   12. </binding>
   13. </basicHttpBinding>
   14. </bindings>
   15. <client>
   16. <endpoint address="http://localhost:8000/Customer/CustomerService"
   17. binding="basicHttpBinding" bindingConfiguration="basicHttp" contract="CustomerProxy.ICustomer" name="basicHttp" />
   18. </client>
   19. </system.serviceModel>
   20. </configuration>
8. Double click on "program.cs" to open the file
9. Copy and paste below specified code into Main() method of "program.cs"
   
   1. using System;
   2. using DemoInterfaces;
   3. using System.ServiceModel;
   4. namespace DemoClient
   5. {
   6. class Program
   7. {
   8. static void Main(string[] args)
   9. {
   10. CustomerProxy.CustomerClient proxy = new DemoClient.CustomerProxy.CustomerClient();
   11. //Binding and Endpoint information is retrieved from
   12. //App.config
   13. string result = proxy.SayHello("Test Client");
   14. Console.WriteLine("Server says : " + result);
   15. Console.WriteLine("Press <Enter> to stop client...");
   16. Console.ReadLine();
   17. }
   18. }
   19. }
10. Compile the solution and run the host project first, followed by the client project.
11. The client console output will be displayed as:
    
    

Conclusion