如何避免必须传递IConfiguration和IHostingEnvironment

Question

I am looking at refactoring and abstracting some code for learning purposes.

I have created this class:

using System;

namespace app.Classes
{
    public class Emailer : ISender
    {

        public Emailer(IConfiguration config, IHostingEnvironment env)
        {
        }
    ...
}

Then I have another class I would like to use that class:

namespace app.Notifications
{
    public class PasswordReset : INotification
    {
        Emailer emailer = new Emailer();

        public PasswordReset()
        {
        }
    ...
}

Since the IConfiguration and IHostingEnvironment are using DI, how do I keep from having to pass them through when I instantiate a new Emailer inside PasswordReset?

Answer 1

Instead of having PasswordReset create a new instance of Emailer , you should leverage the existing DI and turn Emailer into a Service.

Inside the ConfigureServices() method in Startup.cs , add a reference to your Emailer class:

services.AddScoped<ISender, Emailer >();

Then change PasswordReset to reference your new ISender service:

namespace app.Notifications
{
    public class PasswordReset : INotification
    {
        private ISender _emailer;

        public PasswordReset(ISender emailer)
        {
            _emailer = emailer;
        }
    ...
}

Now you no longer need to worry about passing anything around, DI is handling it for you.