How do I use Cascading DropDown with other data sources?
Although the sample for the Cascading Drop Down extender works with XML data, it can just as easily work with any other data source such as a database or active directory. We have provided an example in the walkthroughs that discusses how to do this with a database. If you look carefully at the sample, you’ll see that all it really does is call a webservice that returns an array of CascadingDropDownNameValue objects. To work with other data sources, just change the implementation of this web method to iterate over your data, build up an array of CascadingDropDownNameValue objects from it, and return this array. If you’re having problems getting this to work, be sure that the parameters of your web methods are exactly the same as in the sample/walkthrough (a requirement of ASP.NET AJAX) and that you’re returning and empty array of objects for the case where there are no results. Related threads: CascadingDropDown and Database Cascading Dropdown List VB error 7.2 CascadingDropDown not po
