Take a look at this very interesting blog post series - 31 days of refactoring
The various refactoring “methods” are getting more complex and interesting as the series continues.
IMHO, This is must read for all developers.
In a code behind file (like .cs file), one can use aliases for the namespaces like
using myAlias = System.MyNamespace;
But to achieve the same functionality in an .aspx page you can use something like this
<%@ Import Namespace="myAlias=System.MyNamespace" %>
Note: There should not be any spaces in the namespace value. For example you cannot use something like Namespce=”myalias [...]