follow the steps to write web service in c# programming language-
opening a text editor,put the codes below and save the file as
web.asmx-
<%@ WebService Language="C#" class="WebService1" %>
using System;
using System.Web.Services;
[WebService(Namespace="http://www.yoursite.com/webservices/")]
class WebService {
[WebMethod]
public string SayingSomething() {
return "Hello all";}}

all asp.net handlers implement the interface of IHttpHandler located
in the namespace of System.Web.ISAPI(Internet server application
programming interface) extensions are somehow analogous to Handlers.

Asp.net caching helps you to create high performance applications.
you can cache objects like DataSets,or your created objects.you can
also do page level caching if you used user controls in the page
if your aspx page includes lots of work.

It's a good idea to identify the errors at run time to detect
and handle it. .Net framework has built in mechanism for that.
these exceptions occurs because of user,logic and system errors.

System.Net namespace is for dealing with networking.It
is concerned with operations like downloading, uploading
files,making requests by http protocols.

beginners of .net programming can't guess sometime that
how easy is sending mail through .net.there are many ways
to do that.but i am writing here the easiest method to send
mail in c# with .net.It doesn't involve a lot's of coding.
all is built in and no more components.

we all know well that the DataGrid is used for database work.we
can use DataGrid contorl to show data from database tables.
but it's that the new version of the DataGrid control in the c#
language and Vb.net is able to show any other objects
of classes which implements IList interface.

to display the help and let the users easily get help
whenever they need it you can call the Help.ShowHelp
method in your form.

master pages creates a common look in your application.
if we think about the header and footer in our pages,we
create these header and footer in every aspx pages.this
method has disadvantages.if there were any custom page
which dynamically adds header and footer then would be
good.

The abstract class indicates that a class may be used
as a base class for other classes and is not instantiable.