Error when calling two fullTrust apps on the load of the page

Question

I have a UWP app that does the recording and calling functionality. For this I have added two FullTrust Apps using Desktop bridge application. When I call just one fullTrust app everything works perfectly, but when I call two FullTrust apps by passing parameters (of the FullTrust apps to be started) the the first app that was started behaves incorrectly. For these two FullTrust apps I have used two different Appservice names declared in the Package.Manifest file of the Windows Packaging Project.

I have noticed that whenever I switch the position of the Fulltrust app call the last application that is called always remains active(has the priority of the Appservice connection) even if both has different app service names.

Here is the code I have added when user opens a page in UWP that starts Win32 app and background App

if (ApiInformation.IsApiContractPresent("Windows.ApplicationModel.FullTrustAppContract", 1, 0)) { await FullTrustProcessLauncher.LaunchFullTrustProcessForCurrentAppAsync("Win32"); } if (ApiInformation.IsApiContractPresent("Windows.ApplicationModel.FullTrustAppContract", 1, 0)) { await FullTrustProcessLauncher.LaunchFullTrustProcessForCurrentAppAsync("Background"); }

In the above code, the first app that is Started calls my Win32.exe and second background.exe.

How can I call these two apps independently? whenever we want to start them and close whenever required or may be in future I would like to start two apps at the same time but also I may need to close any app whenever required. Can anyone tel me how can I handle the correct communication path when calling two fullTrust apps at the same time?

Answer 1

How can I call these two apps independently?

For launching multiple desktop app, we suggest to make Launcher app to manage multiple apps, then call LaunchFullTrustProcessForCurrentAppAsync(string parameterGroupId) and pass GroupId parameter. And at first we need add the group in the desktop bridge appxmanifes file.

<Extensions>
  <desktop:Extension Category="windows.fullTrustProcess" Executable="Launcher\Launcher.exe">
    <desktop:FullTrustProcess>
      <desktop:ParameterGroup GroupId="Background" Parameters="/background" />  
      <desktop:ParameterGroup GroupId="Win32" Parameters="/win32" />
    </desktop:FullTrustProcess>
  </desktop:Extension>
</Extensions>

Then use the Launcher to start all apps with parameter

static void Main(string[] args)
{
    // determine the package root, based on own location
    string result = Assembly.GetExecutingAssembly().Location;
    int index = result.LastIndexOf("\\");
    string rootPath = $"{result.Substring(0, index)}\\..\\";

    // process object to keep track of your child process
    Process newProcess = null;

    if (args.Length > 2)
    {
        // launch process based on parameter
        switch (args[2])
        {
            case "/background":
                newProcess = Process.Start(rootPath + @"FullTrust_Background\FullTrust_Background.exe");
                break;

            case "/win32":
                newProcess = Process.Start(rootPath + @"FullTrust_Win32\FullTrust_Win32.exe");
                break;             

        }
    }
}

For more detail please refer this tutorial.