Conversion of Wpf project from .Net framework to .Net5

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Conversion of Wpf project from .Net framework to .Net5

BigH61 581

I am trying to migrate a project I found on GetHub NTwainScanProject

from .Net Framework 4.5 to .Net5.

The original code relied on the following third party applications as well as others
GalaSoft.MvvmLight
GalaSoft.MvvmLight.Extras
GalaSoft.MvvmLight.Platform
PropertyChanged

I have removed the above reference as they are incompatible with .Net5 and added the following
Microsoft.Extensions.DependencyInjection
Microsoft.Toolkit.Mvvm
I have made a number of changes but unsure if they are correct as I am unable to resolve the following conversion from GalaSoft.MvvmLight.Ioc

public ViewModelLocator()
{
         ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
         SimpleIoc.Default.Register<MainViewModel>();
}

Any assistance in converting the above or the whole project would be much appreciated.

Castorix31 91,506 Reputation points

2022-03-14T14:12:06.597+00:00

For scanning, use WIA, which has replaced Twain...
BigH61 581 Reputation points

2022-03-15T10:54:53.13+00:00

@Castorix31 Thankyou for your response. This certainly does look a cleaner solution to implement, however with NTwain you can use "ShowTwainUI" to show the Scanner UI. The closest I have found within WIA is "ShowAcquireImage" and "ShowItemProperties". I assume from the title "ShowTwainUI" that this is an interface specifically used by Twain and not available through WIA?
Castorix31 91,506 Reputation points

2022-03-15T14:50:30.693+00:00

IWiaDevMgr2::GetImageDlg shows this dialog :

Answer accepted by question author

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Castorix31 91,506 Reputation points

2022-03-14T14:12:06.597+00:00

For scanning, use WIA, which has replaced Twain...
BigH61 581 Reputation points

2022-03-15T10:54:53.13+00:00

@Castorix31 Thankyou for your response. This certainly does look a cleaner solution to implement, however with NTwain you can use "ShowTwainUI" to show the Scanner UI. The closest I have found within WIA is "ShowAcquireImage" and "ShowItemProperties". I assume from the title "ShowTwainUI" that this is an interface specifically used by Twain and not available through WIA?
Castorix31 91,506 Reputation points

2022-03-15T14:50:30.693+00:00

IWiaDevMgr2::GetImageDlg shows this dialog :

Answer 1

Michael Taylor 61,106

GalaSoft recommends you switch to CommunityToolkit.Mvvm. Therefore I'd recommend you first migrate your app over to this. Since it supports .NET Standard 2.0 you can do this in your existing project.

Once you've switched to the newer library then switch to .NET 5 from there using the guidelines given here. Actually you'll want to target .NET 6 as .NET 5 is not supported as of late spring of this year.

Note that Winforms/WPF are a little different than just migrating a console app over. I would probably recommend that you create a brand new WPF project targeting .NET 6. This will contain the necessary project settings to work properly with WPF under .NET 6. Then either copy the relevant sections to your existing project or move your code over to the new project. In my experience this reduces the likelihood of something not working properly. For example Winforms has a special build property that enables the designer. Without it the designer doesn't work properly. Posting a question in the forums related to this would be hard to diagnose unless someone knew you migrated your existing project and therefore were missing a property that is automatically set on new projects.

BigH61 581 Reputation points

2022-03-15T10:42:49.02+00:00

@cooldadt Thank you for your response and apologies if my question was unclear but I had already undertaken the solution you had suggested but my problem is that I am having difficulties converting the segment of code indicated.
Michael Taylor 61,106 Reputation points

2022-03-15T14:24:36.457+00:00
Your question is really around DI (dependency injection). In your previous code you were using SimpleIoc. You mentioned you added the MS DI implementation. Does that mean you are now using the .NET 5 DI infrastructure and not SimpleIoc? Are you trying to use the Community Toolkit at all as a replacement for GalaSoft or are you sticking with pure WPF?

If you're using MS's DI implementation then ultimately you'll need to manage the DI scope yourself. That is generally done at app startup. But you need to store the fully built IServiceProvider implementation somewhere. That needs to be done early in the app's lifetime. Since this is a maintenance issue you might want to use reflection to find them.

public class Program { static Task Main ( string[] args ) { var host = CreateHostBuilder(args).Build(); { return host.RunAsync(); }; } static IHostBuilder CreateHostBuilder ( string[] args ) { return Host.CreateDefaultBuilder(args) .ConfigureServices(ConfigureServices); } static void ConfigureServices ( HostBuilderContext context, IServicesCollection services ) { //Register your ViewModels services.AddTransient<MainViewModel>(); } }

Michael Taylor 61,106

To access the services outside DI (because WPF doesn't integrate with it) then you'll need to expose IServiceProvider or equivalent in a global class.

   public class Program  
   {  
      static Task Main ( string[] args )  
      {  
          //Use a field instead of local variable  
          using (_host  = ...)  
          {  
             return _host.RunAsync();  
          };                
      }  
      
      public static IServiceProvider Services => _host.Services;  
      private static IHost _host;  
   }

To get the view model in another code use the global.

   void GetSomething ()  
   {  
      var instance = Program.Services.GetRequiredService<MainViewModel.();  
   }

Note that I'm using the GetRequiredService extension method.

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Conversion of Wpf project from .Net framework to .Net5

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