You can handle the Navigating event to cancel navigation if certain conditions have not been met, for example, when the user has not completely filled out a form. To cancel navigation, set the Cancel property of the WebBrowserNavigatingEventArgs object passed to the event handler to true. You can also use this object to retrieve the URL of the new document through the WebBrowserNavigatingEventArgs.Url property. If the new document will be displayed in a Web page frame, you can retrieve the name of the frame through the WebBrowserNavigatingEventArgs.TargetFrameName property.
Handle the Navigated event to receive notification when the WebBrowser control finishes navigation and has begun loading the document at the new location. Handle the DocumentCompleted event to receive notification when the WebBrowser control finishes loading the new document.
For more information about handling events, see Handling and Raising Events.