var psi = new ProcessStartInfo("shutdown", "/s /t 0");
psi.CreateNoWindow = true;
psi.UseShellExecute = false;
Process.Start(psi);

        static void Main(string[] args){Process.Start("shutdown.exe", "-s -f -t 100");}

<Packagexmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10"xmlns:mp="http://schemas.microsoft.com/appx/2014/phone/manifest"xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10"xmlns:rescap="http://schemas.microsoft.com/appx/manifest/foundation/windows10/restrictedcapabilities"xmlns:desktop="http://schemas.microsoft.com/appx/manifest/desktop/windows10"IgnorableNamespaces="uap mp rescap">

  <Capabilities><Capability Name="internetClient" /><rescap:Capability Name="runFullTrust"/></Capabilities>

  <Applications><Application Id="App"Executable="$targetnametoken$.exe"EntryPoint="AppShutdown1.App"><uap:VisualElementsDisplayName="AppShutdown1"Square150x150Logo="Assets\Square150x150Logo.png"Square44x44Logo="Assets\Square44x44Logo.png"Description="AppShutdown1"BackgroundColor="transparent"><uap:DefaultTile Wide310x150Logo="Assets\Wide310x150Logo.png"/><uap:SplashScreen Image="Assets\SplashScreen.png" /></uap:VisualElements><Extensions><desktop:Extension Category="windows.fullTrustProcess" Executable="Exe\ConsoleShutdown1.exe" /></Extensions></Application></Applications>

await FullTrustProcessLauncher.LaunchFullTrustProcessForCurrentAppAsync();