Here's the situation, I have a listbox that contains names in this format "last name, first name". I also have a textbox that the user types can type a string to pull up the appropiate name, i.e. if the user types in "S" I want the listbox to move to the "S" section, or even better only display names that start with "S".

"Smith, Ro" would bring up "Smith, Robert" (or any other Smith with a first name that starts with "Ro". I'm not sure how I can accomplish this and not kill program response time. The listbox could contain any number of items (probably less than 100, but upwards of 100 is possible.

Another question, how many items can a listbox hold without a serious slow down in response time?