Consuming Wcf Service

1.  First thing to consume a service is to create proxy.
2.  Proxy is a class which client should prepare in client language based on service information.
3. W3 standards for describing service information in WSDL[Webservice Description Language]

 We can create two types of Proxy’s:

1. On-fly Proxy.

2. Strong (or) design time proxy.

Normally code in client is written based on proxy.

1. On-fly Proxy: On-fly proxy means Proxy created @ runtime only. It is not user-friendly but provides dynamic processing advantages.
2. Design time proxy: Proxy is created first and code is written based on proxy. These are more friendly & more preferred also for regular service consumption.

As a wcf developer and consumer we have to handle these two tasks.i.e, Creating bindings according to requirement and creating proxy based on app properly.One proxy is created for single endpoint.

• Previous we Developed one Service Called WCFDEMO. Now we consume that WCFDEMO service at client Side.
• Ensure that WCFDEMO service is Running.

Consuming WCF Service example:

• ChannelFactory<t> class is used to create On-Fly proxy.It is present in same System.ServiceModel namespace.

Steps for Consuming WCF Service :

• Start another Microsoft  VisualStudio instance sothat we can write client program here and comminicate with running wcf service.

                    File-->new Project-->ConsoleApplication[Named As YMsgr]

• Copy (or) Get the interface created in service to our client project [WCFDEMO]  sothat we can use ChannelFactory class for creating proxy.
• Write code in Main,which is starting point.Code to use ChannelFactory and create On-Fly proxy class then start requesting .

     using System;

     using System.Collections.Generic;

     using System.Linq;

     using System.Text;

     using System.ServiceModel;//add reference

    namespace YMsgr

    {

       [ServiceContract]

       interface IDemo

       {

       [OperationContract]

        string Msg();

        string Add();

    }

     

   public class Program

    {

        static void Main(string[] args)

        {

            ChannelFactory<IDemo> obj = new ChannelFactory<IDemo>(new       BasicHttpBinding(),new EndpointAddress("http://localhost:5990/sudhakarservice")));

            IDemo Proxyobj = obj.CreateChannel();//CreatesProxy

            string msg = Proxyobj.Msg();

            Console.WriteLine("Result:"+msg);

            Console.ReadKey();

         }

      }

   }

ScreenShots For Above Program:

1. File-->new Project-->ConsoleApplication[Named As YMsgr]

    2.Add Reference System.ServiceModel for create >net enabled Program to Wcf                 enabled Program

Steps for creating wcf service

•   Start VS2010 in Administrator Mode.

• Start a Console application and wcf library/runtime to current project. And then add reference:System.ServiceModel.dll.Wcf recommends interface pattern for define contracts for users so Add New ItemàCreate interface with required methods and then add wcf attributes to it.  [ServiceContract],[OperationContract]… etc., 
•  Once interface is defined, implement it in class with no wcf content  i.e., just like any normal .Net class extending interface.
• Finally in main method which is starting point write code to host as well as define endpoints.
• Execute and observe wcf service running.

A Sample Program(WCFDEMO):

1.  Write code in IDemo.cs  As follows

                            using System; 

                            using System.Collections.Generic; 

                            using System.Linq;

                            using System.Text;

                            using System.ServiceModel;

                             namespace WCFDEMO

                             {

                                         [ServiceContract]

                                        interface IDemo

                                        {

                                                 [OperationContract]

                                                   string Msg();

                                                   string Add();

                                        }

                               }

2.  Write code in Demo.cs as follow

                          using System;

                          using System.Collections.Generic;

                          using System.Linq;

                          using System.Text;

                         namespace WCFDEMO

                          {

                             public class Demo:IDemo //Extending Interface

                            {

                            public string Msg()

                            {

                               Console.WriteLine("Hello Wolrd");

                                  return "Service Created";

                            }

                            public string Add()

                            {

                               throw new NotImplementedException();

                              }

                          }

                        }    

3.  Write code in Program.cs as follow

           using System.Linq;

           using System.Text;

           using System.ServiceModel;

           namespace WCFDEMO

           {

            public class Program

            {

              static void Main(string[] args)

              {

           ServiceHost obj = new ServiceHost((typeof(Demo)));

           obj.AddServiceEndpoint(typeof(IDemo), new BasicHttpBinding(), "http://localhost:5990/sudhakarservice");

           obj.Open();

           Console.WriteLine("U R Service is Running... to Terminate enter Any Key");

           Console.ReadKey();

           obj.Close();

        }

    }

}

            

•  Execute above WCFDEMO service.
•  To check service is running or not in our system.
•  Go to cmd prompt then type netstat -a 

Imp Points to Note: 

• A service must have minimum one endpoint in our system. 
• Every endpoint contains  Address,Binding and Contract.