如何使用Asp.Net Core 2.0在MVC 6中初始化和使用自定义/支持类

Question

public sealed class SessionContext
{
    private ISession httpContext;
    public  SessionContext(ISession httpContext)
    { 
        this.httpContext = httpContext;
    } 
    public string UserType
    {
        get
        {
            return httpContext.GetString("_UserType");
        }
        set
        {
            httpContext.SetString("_UserType", value);
        }
    }
    ...... More properties ..... 
 }

public class HomeController : Controller
{
    private AppSettings _appSettings; 
    private SessionContext session = null;
    private readonly IHttpContextAccessor _httpContextAccessor;
    private ISession httpContext => _httpContextAccessor.HttpContext.Session;   
//I don't like this constructor as it is getting initialize or every controller call.
    public HomeController(IOptions<AppSettings> myAppSettings, IHttpContextAccessor httpContextAccessor)
    {
        _appSettings = myAppSettings.Value;
        _httpContextAccessor = httpContextAccessor;
        appSettings = new AppSettings(_appSettings);  //Should initialize only once.
        session = new SessionContext(httpContext);  
    }
}

我对...有疑问

1. 如何使用Asp.Net Core 2.0在MVC 6中初始化和使用自定义/支持类当我初始化这些类时，它们会初始化或每个控制器调用。这非常多余。
2. 我的SessionContext类每次都重新初始化。所以当我从另一个控制器调用这个类时，我正在丢失这些值。 我尝试过这种方法，但没有多大用处。 services.AddSingleton（）;

Answer 1

从问题转到答案：

public void ConfigureServices(IServiceCollection services)
{
   services.AddOptions();
   services.AddSingleton<SessionContext, SessionContext>(); 
//calling the extension class to instantiate the classes which we require earlier.
   services.AddMyProjectHelper(Configuration)  
}

创建了一个扩展类...初始化支持类

public static class MyProjectHelperExtensions
  {
        public static IServiceCollection AddMyProjectHelper(this IServiceCollection services, IConfiguration configuration)
        {
            var section = configuration.GetSection("AppSettings");

           // we first need to create an instance
            var settings = new AppSettings();

           // then we set the properties 
            new ConfigureFromConfigurationOptions<AppSettings>(section).Configure(settings); 

           var session = services.BuildServiceProvider().GetService<SessionContext>(); 

           // then we register the instance into the services collection
            services.AddSingleton<MyProjectHelper>(new MyProjectHelper(settings, session));

           return services;
        }
}

最后，控制器ctor使用DI作为所需的类。现在我避免了支持类的冗余初始化。

public SecurityController(MyProjectHelper objHelper, SessionContext sessionContext)
{ 
   session = sessionContext;
   projectHelper  = projectHelper  ?? objHelper; 
}

现在，我能够共享我在支持类中设置的会话变量

private SessionContext session = null;
public HomeController(SessionContext sessionContext)
{
   session = sessionContext;
}

[Authorize]
public IActionResult Index()
{
   if (session.CurrEmployee != null)
   {
      ViewBag.Name = (session.CurrEmployee.FirstName + " " + session.CurrEmployee.LastName);
      return View();
   }
}