Use the using directive to create an alias for a long namespace or class name. You can then use it anywhere you normally would have used that class or namespace. The using alias has a scope within the namespace you declare it in. Sample
// Namespace:
using act = System.Runtime.Remoting.Activation;
// Class:
using list = System.Collections.ArrayList;
...
list l = new list(); // Creates an ArrayList
act.UrlAttribute foo; // Equivalent to System.Runtime.Remoting.Activation.UrlAttribute foo
using act = System.Runtime.Remoting.Activation;
// Class:
using list = System.Collections.ArrayList;
...
list l = new list(); // Creates an ArrayList
act.UrlAttribute foo; // Equivalent to System.Runtime.Remoting.Activation.UrlAttribute foo