ASP.NET in a Nutshell

Creating a Web Service

There are two different coding techniques with which one can construct a web service: inline code and code-behind.

Web Service with Inline Code

Creating a single-file web service is quite simple. All that’s required is to create a new file, add an @ WebService directive and a class containing the implementation for the methods you want to expose, and decorate the methods to be exposed with the WebMethod attribute. The @ WebService directive supports the following attributes:

Class

Specifies the name of the class containing the implementation of the web service. This attribute is necessary to allow the ASP.NET runtime to locate the compiled class at runtime.

CodeBehind

Specifies the name of a code-behind file that contains the class that implements the web service. This attribute is used by Visual Studio .NET when building the project containing the code-behind class.

Debug

Specifies whether the web service should be compiled with debug symbols.

Language

Specifies the language used for code written inline in the .asmx file.

To demonstrate the creation of a web service, look at Example 4-1, which implements a simple “Quote of the Day” web service.

Example 4-1. Quote of the day application (Qotd.asmx)

<%@ WebService Language="VB" Class="Qotd" %> Imports System Imports System.Data Imports System.Web Imports System.Web.Services Public Class Qotd <WebMethod( )> _ Public Function GetQotd( ) As String Dim QuoteDS As New DataSet( ) Dim Context As HttpContext ...