Use .NET framework 4.0 and Visual Studio 2010 to create a WCF service application

1.  Start Visual Studio 2010.
2.  On the File Menu, point to new and then click on Project.
3.  In the New Project dialog box expand visual c# node and then select WCF template.
4.  From Project type window select WCF service application.
5.  Type Name and Location of project and then click on OK button.

By performing these steps you can create a first WCF application with default template.

Now rename name of the file IService.svc to HelloWorld.svc and IService.cs to IHelloWorld.cs. This is not mandatory as I had done it on my sample you can put any name you want.

Creating ServiceContract

[ServiceContract] attribute is used to create a contract. For creating WCF application you need to create a ServiceContract. We use following codes to create a ServiceContract.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
  
namespace HelloWorldService
{
    [ServiceContract]//This attribute is used to create a ServiceContract.
     public interface IHelloWorld //Create a interface which defines contract
    {
        [OperationContract]   //Use [OperationContract] attribute to declare a method which will be accessiable via client.
        string GetMessage();
    }
  
}
  
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
  
namespace HelloWorldService
{
     //Implement IHelloWorld interface and override GetMessage() method displlay a message.
     public class HelloWorld :  IHelloWorld
    {
        public string GetMessage()
        {
            return string.Format("Wow! You have successfully created first WCF application.");
        }
    }
}
 

Now build application and then execute it by pressing F5 key. By performing these steps you will see following dialog box which is known as WCF Test Client window.

Now double click on getMessage() label followed by click on Invoke button and you get desired result.