Add an event handler for the NavigationStarting event. A frame navigation will raise a NavigationStarting event and a CoreWebView2.FrameNavigationStarting event. All of the FrameNavigationStarting event handlers for the current frame will be run before the NavigationStarting event handlers. All of the event handlers share a common NavigationStartingEventArgs object. Whichever event handler is last to change the NavigationStartingEventArgs.Cancel property will decide if the frame navigation will be cancelled. Redirects raise this event as well, and the navigation id is the same as the original one.

Navigations will be blocked until all NavigationStarting and CoreWebView2.FrameNavigationStarting event handlers return.