Virtuemart 2 for joomla is a very good extension to sell products
through website.To add product manually by code, they have doc on
how to use the Api to achieve this, but it may be hard to implement
there Api to add product.So i show here how to do that without using
Api but the simpla way using sql queries -

you can easily add dynamic column in GridView control
with data.there are many dynamic fields you can add
like hyperlink field,bound field,etc.

You can show wall posts of any public facebook page/group/profile
using Graph api in your website if you know javascript & jquery.

you have tried to show data in the asp.net textbox
control and wanted that user will not be able to
modify data in the textbox or cursor will not be
shown in the textbox or other technical reason
then this tips can help you -

Asp.net makes it easy to export tabular data to excel file.It's
easier to use GridView control data to export to excel.the following
codes shows how u can achieve this along with some header info at the
top of the data rows in excel -

An extension that has a security issue or a flaw because of its poor coding can be said as a vulnerable joomla extension.

To protect your site affecting from the vulnerable issues follow the below steps:

verbatim string is a string which is interpreted
by the compiler exactly as it is written, meaning
that even if the string spans multiple lines
or keeps escape characters,etc.