WEB Service

web service

A web service is a web-based functionality accessed using the protocols of the web to be used by the web applications. There are three aspects of web service development:

• Creating the web service
• Creating a proxy
• Consuming the web service

Creating a Web Service

A web service is a web application which is basically a class consisting of methods that could be used by other applications. It also follows a code-behind architecture such as the ASP.NET web pages, although it does not have a user interface.

To understand the concept let us create a web service to provide stock price information. The clients can query about the name and price of a stock based on the stock symbol. To keep this example simple, the values are hardcoded in a two-dimensional array. This web service has three methods:

• A default HelloWorld method
• A GetName Method
• A GetPrice Method

Take the following steps to create the web service:

Step (1) : Select File -> New -> Web Site in Visual Studio, and then select ASP.NET Web Service.

Step (2) : A web service file called Service.asmx and its code behind file, Service.cs is created in the App_Code directory of the project.

Step (3) : Change the names of the files to StockService.asmx and StockService.cs.

Step (4) : The .asmx file has simply a WebService directive on it:

<%@ WebService Language="C#" CodeBehind="~/App_Code/StockService.cs" Class="StockService" %>

Step (5) : Open the StockService.cs file, the code generated in it is the basic Hello World service. The default web service code behind file looks like the following:

using System;

using System.Collections;

using System.ComponentModel;

using System.Data;

using System.Linq;

using System.Web;

using System.Web.Services;

using System.Web.Services.Protocols;

using System.Xml.Linq;

namespace StockService

{

   // <summary>

   // Summary description for Service1

   // <summary>

  

   [WebService(Namespace = "http://tempuri.org/")]

   [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

   [ToolboxItem(false)]

  

   // To allow this Web Service to be called from script,

   // using ASP.NET AJAX, uncomment the following line.

   // [System.Web.Script.Services.ScriptService]

   

   public class Service1 : System.Web.Services.WebService

   {

      [WebMethod]

     

      public string HelloWorld()

      {

         return "Hello World";

      }

   }

}

Step (6) : Change the code behind file to add the two dimensional array of strings for stock symbol, name and price and two web methods for getting the stock information.

using System;

using System.Linq;

using System.Web;

using System.Web.Services;

using System.Web.Services.Protocols;

using System.Xml.Linq;