I've split my solution into business layer (class objects), data layer (SQL specific), and UI layer (forms and user controls). I can add a datasource for my class objects within the main project but I can't do the same at my UI level where I need it.

I have an openning form in my main project which I can drag and drop the datasource objects to the form with no problem. However, I need this functionality in my UI form objects which are contained in a seperate project (.dll) which I reference in my main project.

When I try to add a datasource at my UI level I get the following problem: I select Object as my datasource and then select next. I get the following error: An unexpected error has occurred - Error Message: Object reference not set to and instance of an object.

Any ideas?

can you post the code please..

Thanks for your reply. This is not to do with code. I can't get to that step. This is to do with selecting classes as data source objects using the Data Sources tab within the IDE.