The RadNavigationViewItem inherits ButtonBase and as such provides you with a standard ICommandSource implementation. This means that you can bind the items to commands that will get executed when an item is clicked. For this purpose the following properties can be used.
Command: Gets the command that will be executed when the command source is invoked.
CommandParameter: Represents a user defined data value that can be passed to the command when it is executed.
CommandTarget: The object that the command is being executed on.
The command property can be set to any command that implements the ICommand interface, for example the DelegateCommand.