Occurs before changing the current View's DetailView.ViewEditMode property value.
public event EventHandler<CancelEventArgs> ViewEditModeChanging
Public Event ViewEditModeChanging As EventHandler(Of CancelEventArgs)
The event handler receives an argument of the CancelEventArgs type.
By default, this event is raised when the Edit, SaveAndClose or Cancel built-in Action is executed. This behavior is provided by the WebModificationsController. So, it makes sence is ASP.NET Web applications only.