The ControlValueChanged event handler receives an argument of the EventArgs type.
Handle this event to perform custom actions with the newly set control value.
The ControlValueChanged event is raised in the OnControlValueChanged method. However, this method is not called in the PropertyEditor class, because there is no access to the actual control that displays the bound property. So, in the PropertyEditor class' descendants, call the OnControlValueChanged method after the control's value has been changed. This is recommended because the built-in Windows Forms LockController subscribes to the ControlValueChanged event to check whether the property bound to the Property Editor is modified in another View at the same time. If so, this Controller shows a confirmation message so that an end-user can resolve this situation. The built-in Windows Forms Property Editors call the OnControlValueChanged method in the EditBase.EditValueChanged event handler (EditBase is the basic class of editors from the XtraEditors library).
The LockController is designed for Windows Forms applications only. So, in ASP.NET descendants of the PropertyEditor class, you do not have to call the OnControlValueChanged method if it is not required for your custom actions.