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.

you can use online paypal buy button in your page
for receiving online paypal payment.when users click
this buy button they will enter in payment page
for payment.

command objects use parameters for passing values
to sql statements for type cheking,validation,guarding
against SQL injection attacks,etc.so its a good practice
to use command parameters to sql statements.

It's nice to show cool gradient color as a
background color of the form in c#.net desktop
application.you can set different colors.

upgrading dnn website to upper version is easy.one
have to follow the following steps to do upgrading.

The great control in the asp.net ajax is the update
panel control.it can be added to almost every
asp.net page almost magically.this control when
used with a ScriptManager permits a programmer to
use partial rendering(a technique by which many
sections of page updated partially without reloading
the entire page).