ClickOnce allows two "Install Modes": available online only, available offline as well.

With offline mode, the ActivationUri is not available. Instead, you can access:

AppDomain.CurrentDomain.SetupInformation.ActivationArguments.ActivationData

Launch the offline app by referencing the shortcut from a command line in this form:

"%userprofile%\Desktop\My App Name.appref-ms" arg1,arg2,arg3

Further explanation can be found:

https://robindotnet.wordpress.com/2010/03/21/how-to-pass-arguments-to-an-offline-clickonce-application/

https://developingfor.net/2010/06/23/processing-command-line-arguments-in-an-offline-clickonce-application/