How to use VariantService in a windows application

[Gokul]

We have a windows application where we should be able to use the VariantService from Litium.Products, but the service seems to be not getting resolve successfully.

“InvalidOperationException: Unable to resolve service for type ‘Litium.Products.VariantService’ while attempting to activate ‘IntegrationService.Services.ProductService’.”

if I add service as below it gives another error "‘Cannot instantiate implementation type ‘Litium.Products.VariantService’ for service type ‘Litium.Products.VariantService’.’
"

is there anyway to do it?

Litium version: 8.5

[steve.redstorm]

Variant service inherits from IEntityService so you need to add that also

public abstract class VariantService : IEntityService

and the base looks like this:

[Service(ServiceType = typeof(IEntityService<>), Lifetime = DependencyLifetime.Singleton)]
public interface IEntityService
where T : IEntityKey

[Gokul]

tried both below but still seems to get resolve errors.

‘Cannot instantiate implementation type ‘Litium.Data.Internal.IEntityService1[Litium.Products.Variant]' for service type 'Litium.Data.Internal.IEntityService1[Litium.Products.Variant]’.’

‘Cannot instantiate implementation type ‘Litium.Data.Internal.IEntityService1[T]' for service type 'Litium.Data.Internal.IEntityService1[T]’.’

same error if I use as Singleton.

[steve.redstorm]

How about this:

services.AddScoped<IEntityService<Litium.Products.VariantService>, Litium.Products.VariantService>();

[Gokul]

modified it a bit as

services.AddScoped<IEntityService<Litium.Products.Variant>, Litium.Products.VariantService>();

and getting below error.

‘Cannot instantiate implementation type ‘Litium.Products.VariantService’ for service type ‘Litium.Data.Internal.IEntityService`1[Litium.Products.Variant]’.’

[patric.forsgard]

The Litium.Products.VariantService is the contract and for that the implementation need to be registrated so it is not so simple.

The implementation is dependent on a lot of other services, caching, configuration etc and to make it startup correctly you will add them with the services.AddLitiumApplication(Configuration);, this exists in the Litium.Application assembly. When adding the services.AddLitiumApplication(Configuration) into the services, the full Litium platform will be executed inside this application and not sure if that is what you want.

[Gokul]

is there any other way to just use the variant service? using something similar to IoC.Resolve ?

[patric.forsgard]

No, it’s not.

The implementation of variant service (or other service) in Litium is dependent or the full platform running in the same context.

[Gokul]

tried to add services.AddLitiumApplication(Configuration); but then I get error to add all the services highlighted, and still it fails if I add all those "‘Cannot instantiate implementation type ‘Litium.Connect.Shipments.ShippingProviderService’ for service type ‘Litium.Connect.Shipments.ShippingProviderService’.’
"

[patric.forsgard]

As for the VariantService, you can’t add the contract (abstract class) as the type for the service implementation and that is what you are doing with the yellow marked lines.

To solve that you have two options and both of them includes that you should remove the AddScoped-lines above and:

1. Remove the Litium.Connect.Abstractions assembly in the configuration for plugins
2. Add a package reference to Litium.Connect.Application

[Gokul]

1. Removed Litium.Connect.Abstractions assembly
   

2. Added package reference to Litium.Connect.Application

only having this in start up now

it leads to an error “InvalidOperationException: Unable to resolve service for type ‘Microsoft.AspNetCore.Hosting.Server.IServer’ while attempting to activate ‘Litium.Application.Web.ServerListenerHelperServiceImpl’.” is there something I am missing?

[patric.forsgard]

Are you using the Host.CreateDefaultBuilder(args) as the builder or are you trying to bootstrap the host process as well?