How to use Dependency Injection in .Net core Console Application

Question

I have to add data to my database using a Console Application. In the Main() method I added:

var services = new ServiceCollection();
var serviceProvider = servic         


        

Answer 1

Add services to collection before building provider. In your example you are adding services after already having built the provider. Any modifications made to the collection have no effect on the provider once built.

var services = new ServiceCollection();
var connection = @"Server = (localdb)\mssqllocaldb; Database = CryptoCurrency; Trusted_Connection = True; ConnectRetryCount = 0";
services.AddDbContext(options => options.UseSqlServer(connection));
//...add any other services needed
services.AddTransient();

//...

////then build provider 
var serviceProvider = services.BuildServiceProvider();

Also in the constructor example provided you are still initializing the db.

public AutoGetCurrency(CurrencyDbContext db) =>  this.db = new CurrencyDbContext();

The injected db is not being used. You need to pass the injected value to the local field.

public AutoGetCurrency(CurrencyDbContext db) =>  this.db = db;

Once configured correctly you can then resolve your classes via the provider and have the provider create and inject any necessary dependencies when resolving the requested service.

var currency = serviceProvider.GetService();