Causing the fast scrolling handle to appear is as simple as setting the FastScrollEnabled property to true:
ListView.FastScrollEnabled = true;
Adding a Section Index
A section index provides additional feedback for users when they are fast-scrolling through a long list – it shows which ‘section’ they have scrolled to. To cause the section index to appear the Adapter subclass must implement the ISectionIndexer interface to supply the index text depending on the rows being displayed