Loading dropdownlist from db

I have several stored procedures that I want to use to populate dropdownlists. The storedprocedures all return a number and a corresponding string. Is it possible to store the datareader results in an application variable (these dropdownlists are found all over the site, and I don't want to query the db multiple times for each one)? Is it also possible to display just the string, but return the number from the dropdownlist when the user selects an entry? Is there a better wayt to do this?