How to customize the PrismApplication class or override the Initialize method？

[w757703598]

I have a complex project that has a lot of loading functions in the Initialize, RegisterTypes, etc., which causes the project to start slowly.
So I want to put Initialize and OnInitialized in one thread, and refresh the status through a welcome window to achieve a good interactive experience.
I tried some case:

1. Unable to rewrite InitializeInternal method, I can only rewrite ConfigureViewModelLocator, Initialize, OnInitialized。
2. ThreadManager is used to synchronize threads in order

  public class ThreadManager
  {
      public static ConcurrentQueue<Thread> threads = new ConcurrentQueue<Thread>();

      public static void Run()
      {
          Task.Run(() =>
          {
              while (true)
              {
                  var res = threads.TryDequeue(out Thread t);
                  if (res)
                  {
                      t.Start();
                      while (t.ThreadState != ThreadState.Stopped)
                      {

                      }
                  }
              }
          });

      }
      public static void AddThreadHandle(Action action)
      {
          var thread = new Thread(new ThreadStart(() =>
          {
              action.Invoke();
          }));
          thread.SetApartmentState(ApartmentState.STA);
          thread.IsBackground = true;
          threads.Enqueue(thread);
      }
  }

3. App Code:

    /// <summary>
    /// App.xaml 的交互逻辑
    /// </summary>
    public partial class App : PrismApplication
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            ThreadManager.Run();
            base.OnStartup(e);
        }
        protected override Window CreateShell()
        {
            return Container.Resolve<Shell>();
        }
        protected override void ConfigureViewModelLocator()
        {
            ThreadManager.AddThreadHandle(() =>
            {
                SomeTodo("ConfigureViewModelLocator");
                base.ConfigureViewModelLocator();
            });

        }

        protected override void OnInitialized()
        {
            ThreadManager.AddThreadHandle(() =>
            {
                SomeTodo("OnInitialized");
                base.OnInitialized();
            });

        }

        protected override void Initialize()
        {
            ThreadManager.AddThreadHandle(() =>
            {
                SomeTodo("Initialize");
                base.Initialize();
            });

        }

        protected override void RegisterTypes(IContainerRegistry containerRegistry)
        {

        }

        public void SomeTodo(string message)
        {
            for (int i = 0; i < 10; i++)
            {
                Thread.Sleep(100);
                Console.WriteLine($"{message}:{i}");
            }
        }
    }

4. However, an exception occurred in the method Initialize.:The calling thread cannot access this object because a different thread owns it.
5. Exception occurred in MvvmHelpers. AutowireViewModel (Windows)。So I want to override it. But I can't copy the code directly.

 ContainerLocator.SetContainerExtension(CreateContainerExtension);
 _containerExtension = ContainerLocator.Current;
 _moduleCatalog = CreateModuleCatalog();
 RegisterRequiredTypes(_containerExtension);
 RegisterTypes(_containerExtension);
 _containerExtension.FinalizeExtension();
 ConfigureModuleCatalog(_moduleCatalog);
 RegionAdapterMappings regionAdapterMappings = _containerExtension.Resolve<RegionAdapterMappings>();
 ConfigureRegionAdapterMappings(regionAdapterMappings);
 IRegionBehaviorFactory regionBehaviors = _containerExtension.Resolve<IRegionBehaviorFactory>();
 ConfigureDefaultRegionBehaviors(regionBehaviors);
 RegisterFrameworkExceptionTypes();
 Window window = CreateShell();
 if (window != null)
 {
     MvvmHelpers.AutowireViewModel(window);
     RegionManager.SetRegionManager(window, _containerExtension.Resolve<IRegionManager>());
     RegionManager.UpdateRegions();
     InitializeShell(window);
 }

 InitializeModules();

So did I make a mistake by asking for help？ thanks
XVisionPro.zip

[brianlagunas]

You're taking the wrong approach. You simply want to show a loading screen while you offload the work your application has to do to get setup. The Prism initialization process is fast and is not the source of your issue.

[w757703598]

I must admit The Prism initialization process is fast. It slowed down because I used assembly reflection 、 create database 、Load config. Did I put it in the wrong position?
pseudocode ：

proteced override void OnInitialized()
{ 
    var assemblies=Application.GetAllRefreanceAssemblies();
    foreach (var assembly in assemblies)
    {
         //reflection 
    }
    // InitDatabase 
    // Load Config 
}

The mentioned places are slow to load, so I want to show the loading status on loading screen to the users.
If I'm wrong, what should I do？
thanks!

[thomasgalliker]

I usually navigate to a page which is responsible for app initialization tasks: AppStartPage + AppStartViewModel.

• AppStartPage just shows your app logo or an activity indicator.
• AppStartViewModel has an Initialize method which does all the tasks you mentioned: Load data, configure database,… If everything is done, navigate to the next page, e.g. the LoginPage or any kind of MainPage.