How to tell if user has modified data using bindingsource?

Question

I have a DataGridView bound to a bindingsource which is bound to a List<T>. The user clicks a row that goes to a form with textboxes, etc. The textboxes are databound like so:

if (txtID.DataBindings.Count == 0)
    txtID.DataBindings.Add("Text", bindingSource, "Title");

I want to be able to detect if the user has modified any data in the controls when they click the close button, so I can prompt them to say "You have un-saved work. Do you want to Save?"

How do I detect this on the binding source?

UPDATE: I have worked out that I can do bindingSource.EndEdit() which pushes the changes to my item in the list. In my item, I can then say if Dirty throw a Messagebox but if they click "No" to saving the information, the CancelEdit does not work.

Answer 1

From my updated question I found I had to store a current version of the object at BeginEdit using Memberwise.Clone and then in CancelEdit I restored that to the current.