This event occurs before the component is actually changed, and gives the designer a chance to abort the change or perform any pre-change processing. This event does not occur during form load and unload, because changes are expected at this time.
Requirements
Namespace: System.ComponentModel.Design Assembly: System (in System.dll) Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0