linked dropdown controls?

i want to link 2 drop downs in an asp开发者_JAVA百科.net application.

they will contain release and project data such that each release will have multiple projects.

whats the best and most efficient way to do this?

I was thinking to use ajax for this but dont want a server call each time a new release is selected since this will typically not change ofter so now i am thinking to use caching and bind them to cache objects and havea data dependancy to refresh teh cash once new data is detected.

thoughts?

examples?

I quite like the CascadingDropDown control extenders in the Ajax Control Toolkit. Take a look. It might fit the bill.

http://www.asp.net/ajax/ajaxcontroltoolkit/Samples/CascadingDropDown/CascadingDropDown.aspx