Very often we have a relative URL of some page or resource like "~/img/logo.gif" and we need an absolute URL
to insert it in some control or link (something like "http://www.rezashirazi.com/img/logo.gif")

Asp.Net 2.0 has some very useful methods that could help us to resolve the absolute URL we need.

First of them is Page method ResolveUrl() that converts a relative URL into one that is usable on the requesting client.
This means you we can pass to this method an URL that is relative to the current page, something like this:
and it would return to us a valid relative URL , taking into account the current URL of the Page from where you are calling it.