Define class dynamically with Service Locator - Asp.Net Core - asp.net-core

Question

I am working with Asp.Net Core application. I have two classes namely Online and Offline. I have created interface and defined the methods in these two classes. Based on the need I have to connect to anyone of these two classes.
Previously when I worked in Asp.Net MVC, I have used unity container and Service Locator to specify the class name in XML file for invoking the class dynamically (between online and offline).
Now I want to implement the same with Asp.Net core. But I am not sure how to specify the class name outside for method invocation. Kindly help.
Thanks

Answer 1

In .net core dependency injection is in built. You don't need unity or any other any more.
https://learn.microsoft.com/en-us/aspnet/core/fundamentals/dependency-injection?view=aspnetcore-5.0
You can achieve what you want by using a little tweak.
//// classes
public interface IFileUploadContentProcess
{
IEnumerable<StoreOrder> ProcessUploads(IFormFile file);
}
public class ProcessExcelFiles : IFileUploadContentProcess
{
public IEnumerable<StoreOrder> ProcessUploads(IFormFile file)
{
throw new NotImplementedException();
}
}
public class ProcessCsvFiles : IFileUploadContentProcess
{
public IEnumerable<StoreOrder> ProcessUploads(IFormFile file)
{
throw new NotImplementedException();
}
}
//// register it
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
services.AddTransient<IStoreOrderService, StoreOrderService>();
services.AddTransient<ProcessExcelFiles>();
services.AddTransient<ProcessCsvFiles>();
// Add resolvers for different sources here
services.AddTransient<Func<string, IFileUploadContentProcess>>(serviceProvider => key =>
{
return key switch
{
"xlsx" => serviceProvider.GetService<ProcessExcelFiles>(),
_ => serviceProvider.GetService<ProcessCsvFiles>(),
};
});
}
//use it
public class StoreOrderService : IStoreOrderService
{
private readonly Func<string, IFileUploadContentProcess> _fileUploadContentProcess;
public StoreOrderService(Func<string, IFileUploadContentProcess> fileUploadContentProcess)
{
_fileUploadContentProcess = fileUploadContentProcess;
}
public async Task<IEnumerable<StoreOrder>> UploadStoreOrdersAsync(IFormFile file)
{
//// passing csv to process csv type(default), if xlsx, pass xlsx
var records = _fileUploadContentProcess("csv").ProcessUploads(file);
return records;
}
}

Answer 2

After lot of brainstroming, I found the below solution
Create a class for ServiceLocator
public class ServiceLocator
{
private ServiceProvider _currentServiceProvider;
private static ServiceProvider _serviceProvider;
public ServiceLocator(ServiceProvider currentServiceProvider)
{
_currentServiceProvider = currentServiceProvider;
}
public static ServiceLocator Current
{
get
{
return new ServiceLocator(_serviceProvider);
}
}
public static void SetLocatorProvider(ServiceProvider serviceProvider)
{
_serviceProvider = serviceProvider;
}
public object GetInstance(Type serviceType)
{
return _currentServiceProvider.GetService(serviceType);
}
public TService GetInstance<TService>()
{
return _currentServiceProvider.GetService<TService>();
}
}
Step 2: Create interface and inherit in the classes and define the interface methods
Step 3: Define class name in appSettings.json and read the values in startup.cs
public void ConfigureServices(IServiceCollection services)
{
//reading from appSettings.json
string strClassName = Configuration["DependencyInjection:className"];
if (strClassName == "OnlineData")
services.AddTransient<<<InterfaceName>>, <<OnlineClassName>>>();
if (strClassName == "OfflineData")
services.AddTransient<<<InterfaceName>>, <<OfflineClassName>>>();
}
Step 4: Create object for the dynamic class inside controller/action method
InterfaceNamemyService = ServiceLocator.Current.GetInstance<>();