VPN Background Task?

[michelolvera]

I'm trying to create a VPN Provider for Windows with a background task, there are just a few examples over internet and all of them are written as UWP app. I'm using .NET 8 and WinUI 3, is it still possible to create a VPN background app?

My IBackgroundTask implementation is in a project with <CsWinRTComponent>true</CsWinRTComponent> and the winmd object is created but always same error at runtime:

Application: Vpn.exe
CoreCLR Version: 8.0.123.58001
.NET Version: 8.0.1
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Runtime.InteropServices.COMException (0x8001010E): The application called an interface that was marshalled for a different thread.

The Application Object must initially be accessed from the multi-thread apartment.
   at WinRT.ExceptionHelpers.<ThrowExceptionForHR>g__Throw|39_0(Int32 hr)
   at WinRT.ExceptionHelpers.ThrowExceptionForHR(Int32 hr)
   at ABI.Microsoft.UI.Xaml.IApplicationStaticsMethods.Start(IObjectReference _obj, ApplicationInitializationCallback callback)
   at Microsoft.UI.Xaml.Application.Start(ApplicationInitializationCallback callback)
   at Vpn.Program.Main(String[] args)

Package.appxmanifest:
<Application Id="App"
  Executable="$targetnametoken$.exe"
  EntryPoint="$targetentrypoint$">
  <Extension Category="windows.backgroundTasks" Executable="$targetnametoken$.exe" EntryPoint="Vpn.VpnBackgroundTask" ResourceGroup="tunnel">
    <BackgroundTasks>
	    <uap:Task Type="vpnClient" />
    </BackgroundTasks>
  </Extension>
</Application>

<Capabilities>
	<Capability Name="internetClientServer" />
	<Capability Name="privateNetworkClientServer" />
	<uap:Capability Name="sharedUserCertificates" />
	<rescap:Capability Name="networkingVpnProvider"/>
	<rescap:Capability Name="runFullTrust"/>
</Capabilities>

<Extensions>
    <Extension Category="windows.activatableClass.inProcessServer">
        <InProcessServer>
            <Path>WinRT.Host.dll</Path>
            <ActivatableClass ActivatableClassId="Vpn.VpnBackgroundTask" ThreadingModel="both" />
        </InProcessServer>
    </Extension>
 </Extensions>

[pedasmith]

Short answer: nope, UWP only. It's not possible to make a VPN using the UWP VPN APIs with anything other than a UWP app. Can I ask what's missing from UWP that makes you prefer .NET 8 and WinUI3?

[michelolvera]

I'm just an early adopter. 🤣 I'll work with UWP then, thanks.