Always Get Better

One of the nicest features in ASP.NET is its out-of-box support for relative paths in hyper links and other controls. This is very important for developers whose code resides within the root of their testing environment but within a sub-directory of the production server.

Whereas one would have to carefully program things like image links to point at “/applicationbasepath/images/”, in ASP.NET we can simply use “~/images”. Genious!

When writing custom code, however, the work isn’t done for us automatically. We have to pass our URL to a server-side function in order to convert the “~/” into a base path usable by our visitors.

There are two ways of doing this:

Using Relative Paths From a Web Page or Control

If we are programming a page template or a server control, we can use the ResolveUrl() function provided by our environment context.

[source:c#]
string resolvedUrl = ResolveUrl( “~/index.php” );
[/source]

On AlwaysGetBetter.com, “~/index.php” would resolve to http://www.alwaysgetbetter.com/blog/index.php. On another site, it might resolve to the root such as http://www.abetterblog.com/index.php. Programming this way makes our solution more portable.

Using Relative Paths From Outside a Web Page

Sometimes we need to use relative paths from outside the context of a web page. For example, if we were to make a change in our Global.asx file, the program code we use may not be considered to be within a web page scope.

Fortunately, .NET provides us with the static helper class VirtualPathUtility.

[source:c#]
string redirUrl = VirtualPathUtility.ToAbsolute(“~/redirPage.aspx”);
Response.Redirect( redirUrl );
[/source]