Rocky Lhotka had this over on his site:
The Golden Rule of Windows Forms data binding
Never directly interact with a business object while it is data bound – only interact with the bindingsource
http://forums.lhotka.net/forums/thread/22990.aspx
I have to say, I am guilty of doing this, and I didn’t even know it was considered a bad practice, but I do recall running into problems with the behavior in getting the UI to refresh as I would want it to.
I also found a nice article talking about how to speed up binding to the datagrid: