I have class with constructor for logging and for access to config:

public class SendEmaiServiceProvider
{
    private readonly IConfiguration _config;
    private readonly IWebHostEnvironment _env;
    private readonly ILogger<SendEmaiServiceProvider> _logger;
    private readonly string _fromEmailAddress;


    public SendEmaiServiceProvider(IConfiguration config, IWebHostEnvironment env, ILogger<SendEmaiServiceProvider> logger)
    {
        _config = config;
        _env = env;
        _logger = logger;
        _fromEmailAddress = _config.GetValue<string>("AppSettings:Email:FromEmailAddress");
    }

    public void SayHi()
    {
        Console.WriteLine("Hi");
    }
}

The question is - How to call method SayHi from another class without pushing logger, env and config?

No I initialize new object with parameters, but I sure that it is wrong:

var sendEmaiServiceProvider = new SendEmaiServiceProvider(_config, _env, _logger);
sendEmaiServiceProvider.SayHi();

I can create an empty constructor but I will not have _fromEmailAddress value.

CodePudding user response：

Looks like this is a netcore website. Assuming so, then:

1. Create an interface for the dependency.
2. Register the dependency in Startup.cs
3. Request the dependency as needed from the netcore DI.

public interface ISendEmaiServiceProvider
{
  void SayHi()
}

public class SendEmaiServiceProvider : ISendEmaiServiceProvider
{
  public void SayHi() { }
}

Then in Startup.cs:

public void ConfigureServices( IServiceCollection services )
{
  services.AddScoped<ISendEmaiServiceProvider, SendEmaiServiceProvider>();
}

Then in the Controller (or wherever else DI is used), request it in the .ctor and all the dependencies for SendEmaiServiceProvider will be filled automatically by DI.

public class HomeController : Controller
{
  public readonly ISendEmaiServiceProvider _emailService;

  public HomeController( ISendEmaiServiceProvider emailService )
  {
    _emailService = emailService
  }
}

That should get you going.

CodePudding user response：

You should use dependency injection here. Better you create an interface here and resolve your 'SendEmaiServiceProvider' on the startup. And then use the interface instead of creating a new instance for SayHi() method.

public interface YourInterface
{
  void SayHi()
}

public class SendEmaiServiceProvider : YourInterface
{
  public void SayHi() 
  { 
    //your code
  }
}

On your startup,

public void ConfigureServices( IServiceCollection services )
{
  services.AddScoped<YourInterface, SendEmaiServiceProvider>();
}

On your controller/service,

 public class YourController : Controller
    {
      public readonly YourInterface _emailSenderService;
    
      public HomeController( YourInterface emailSenderService )
      {
        _emailSenderService = emailSenderService
      }
    
     
    
    public IActionResult SayHI()    
    {
    _emailSenderService.SayHi()
    }    
   }