Overview
My previous article provided an Introduction to WCF  (Windows Communication Framework). Now we will discuss the differences between Web Services and WCF concepts.

Web Services (ASMX)
Web Services are used to send/receive messages using the Simple Object Access Protocol (SOAP) via HTTP only. 

It is available in the namespace “System.Web.Services. WebService Class” with a constructor, methods, prosperities and events.

Code

using System;    
using System.Collections.Generic;    
using System.Web;    
using System.Web.Services;    
    
namespace HelloWorldServices    
{    
    /// <summary>    
    /// Summary description for Service1    
    /// </summary>    
    [WebService(Namespace = "http://tempuri.org/")]    
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]    
    [System.ComponentModel.ToolboxItem(false)]    
    public class Service1 : System.Web.Services.WebService    
    {    
    
        [WebMethod]    
        public string HelloWorld()    
        {    
            return "Hello World";    
        }    
    }    
}  

WCF
WCF is used to exchange messages using any format via any transport protocol like HTTP, TCP/IP, MSMQ, Named Pipes and and so on. Its default format is SOAP.

Note: Microsoft Message Queuing (MSMQ) is a messaging queue services developed by Microsoft.
Simple Object Access Protocol (SOAP) is a messaging protocol developed by W3C.

Code: IService1.cs

using System;    
using System.Collections.Generic;    
using System.Linq;    
using System.Runtime.Serialization;    
using System.ServiceModel;    
using System.ServiceModel.Web;    
using System.Text;    
    
namespace HelloWorldWCFService    
{    
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the interface name "IService1" in both code and config file together.    
    [ServiceContract]    
    public interface IService1    
    {    
    
        [OperationContract]    
        string GetData(int value);    
    
        [OperationContract]    
        CompositeType GetDataUsingDataContract(CompositeType composite);    
    
        // TODO: Add your service operations here    
    }    
    
    
    // Use a data contract as illustrated in the sample below to add composite types to service operations.    
    [DataContract]    
    public class CompositeType    
    {    
        bool boolValue = true;    
        string stringValue = "Hello ";    
    
        [DataMember]    
        public bool BoolValue    
        {    
            get { return boolValue; }    
            set { boolValue = value; }    
        }    
    
        [DataMember]    
        public string StringValue    
        {    
            get { return stringValue; }    
            set { stringValue = value; }    
        }    
    }    
}    

Service1.svc 

using System;    
using System.Collections.Generic;    
using System.Linq;    
using System.Runtime.Serialization;    
using System.ServiceModel;    
using System.ServiceModel.Web;    
using System.Text;    
    
namespace HelloWorldWCFService    
{    
    // NOTE: You can use the "Rename" command on the "Refactor" menu to change the class name "Service1" in code, svc and config file together.    
    public class Service1 : IService1    
    {    
        public string GetData(int value)    
        {    
            return string.Format("You entered: {0}", value);    
        }    
    
        public CompositeType GetDataUsingDataContract(CompositeType composite)    
        {    
            if (composite == null)    
            {    
                throw new ArgumentNullException("composite");    
            }    
            if (composite.BoolValue)    
            {    
                composite.StringValue += "Suffix";    
            }    
            return composite;    
        }    
    }    
}