I have inherited a complex application with dozens of controls.

The new functionality I am to surgically insert is to prevent the user
from proceeding further if any of the data is incorrect in my control
on the current page.

I can capture the .Leave event from my control, but I do not want
Windows to honor the destination control that the user clicked.  Is
there such a way to tell Windows to CancelEvents and do not activate
the control that the user clicked?

If there were, this method would be something like:

System.Windows.Forms.Application.CancelEvents(), instead of:

System.Windows.Forms.Application.DoEvents()

Thanks.