ASP.NET controls automatically keep their data
when page is sent to the server in response to
events (like a user clicking a button).
this persistence of data is called view state

List<> can be used as a collection of objects which
can be accessed by index.List originated from
System.Collections.Generic class.List objects can
be sorted,searched,manipulated.so List is very
useful in programming for holding any type of
objects.following shows a example of List<> -

asp.net has default password recovery control and methods
to implement password recovery.you just need to use
asp.net membership provider in your app and add the
PasswordRecovery control in a page by which you want
to recover password.

Ajax is the best technique for showing & updating
data without page refresh.
jquery ajax make things possible easier way.in this
post i will show how to pass data via jquery ajax
and get back data.

using asp.net membership Probvider you can easily
make a user login using username and password and redirect to
default or any page by the following way -

sometimes needed that html tags from a html string
to be removed.there are many purposes to do that.
there are many ways this can be achieved in client side
using jquery and javascript -

there are different kind of joins available by sql like
inner join,left join,etc.by the following example i will show
how to do left join which i used in my application to
get data from two tables -