asp.net-core Dependency Injection Plain Dependency Injection example (Without Startup.cs)
Example
This shows you how to use Microsoft.Extensions.DependencyInjection nuget package without the use of the WebHostBuilder from kestrel (e.g. when you want to build something else then a webApp):
internal class Program
{
public static void Main(string[] args)
{
var services = new ServiceCollection(); //Creates the service registry
services.AddTransient<IMyInterface, MyClass>(); //Add registration of IMyInterface (should create an new instance of MyClass every time)
var serviceProvider = services.BuildServiceProvider(); //Build dependencies into an IOC container
var implementation = serviceProvider.GetService<IMyInterface>(); //Gets a dependency
//serviceProvider.GetService<ServiceDependingOnIMyInterface>(); //Would throw an error since ServiceDependingOnIMyInterface is not registered
var manualyInstaniate = new ServiceDependingOnIMyInterface(implementation);
services.AddTransient<ServiceDependingOnIMyInterface>();
var spWithService = services.BuildServiceProvider(); //Generaly its bad practise to rebuild the container because its heavey and promotes use of anti-pattern.
spWithService.GetService<ServiceDependingOnIMyInterface>(); //only now i can resolve
}
}
interface IMyInterface
{
}
class MyClass : IMyInterface
{
}
class ServiceDependingOnIMyInterface
{
private readonly IMyInterface _dependency;
public ServiceDependingOnIMyInterface(IMyInterface dependency)
{
_dependency = dependency;
}
}
