I came across a requirement for implementing a cascading dropdown for one of my client. Since it was an urgent requirement, I googled it to find a source from codeplex and on other open source forum.
DataCog's cascading dropdown was the first one on the search result. I decided to use the source, but found few enhancements needed to it.
It limited the implementation to parent to child. It implemented a Parent control and a Child control. To use it, your list/library should have a Parent and a child control. You cannot really cascade the effect to multiple level. It was a constraint for me.
I used the source code provided by DataCogs, and eliminated the Parent control by creating couple of properties and it works fine for multiple siblings.
The modified source code is attached.
Comments are welcome.
Updated: The source code attached was the latest one, but the package was not. Uploading the newer file.
SharePointSnippets.UI.Controls.CascadingDropdown.zip (87.64 kb)
Updated [Jan 10, 2009] : I have added a blog on configuration. Click here to view