Years ago when I first started working with SharePoint, I tried to build cascading lists. I wanted them to function something like this:
- A user chooses an item from a drop-down list (e.g. the list is named "Customers" and from the list the user selects "Western Region"
- The next drop-down list is now filtered to just contain those customers in the Western region.
This seemed simple enough, but I couldn't do it. I tried for an embarrassingly long time, certain that it could be done, but I just couldn't figure it out. I searched the Microsoft forums and found it was a common question. Unfortunately, the response was that the cascading list functionality wasn't available out-of-the-box, and that you had to use SharePoint Designer and Visual Studio to accomplish it.
Fast forward to SharePoint 2010. I was curious to know if cascading lists made the cut, so I did some research. While SharePoint 2010 doesn't have cascading lists per se, it does support relationships between lists! Using the previous example, you create a list for Customers and a list for Western Region. You can create a Look-up field from Customers in the Western Region list, and then the lists are related. Using the out-of-the-box "Related Items" Web Part, when you click on "Western Region", the list of customers in that region will become available to choose from.
I realize that there are more noteworthy changes in SharePoint 2010 than this, and soon enough the functionality will just be taken for granted, but I will always appreciate this little improvement!