Accessing Session state outside controller

Question

I am trying to access data saved in Session state, in an ASP.Net Core Web Application, outside the controller, but the httpcontext is always null, how do I send the state over to a class?

I have added the correct statements in Startup.cs, to use sessions.

Furthermore, using this inside the controller works perfectly fine:

HttpContext.Session.SetString("Threshold",threshold);
HttpContext.Session.GetString("Treshold");

both work completely fine when accessing within the controller, yet I want to access this data in another class. Currently I am just using a static variable, but this is of course not the way to go, I want to access the session in here:

public class ImageAnalysisExtensionValues
{
    public static double ConfidenceThreshold { get; set; }
}

(Data has been converted to double).

What do I do?

Answer 1

You can make use of Asp.Net Cores dependency injection and use the IHttpContextAccessor interface.

You have to register it first in your Startup.cs class (it is not always registered as default - therefore the use of TryAddSingleton<>()):

public void ConfigureServices(IServiceCollection services)
{
    // ...
    services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
    // ...
}

Then use it like this:

public YourClassOutsideOfController
{
    private IHttpContextAccessor _contextAccessor;

    public YourClassOutsideOfController(IHttpContextAccessor contextAccessor)
    {
        _contextAccessor = contextAccessor;
    }

    private void YourMethod()
    {
        var context = _contextAccessor.HttpContext;
        context.Session.SetString("Threshold",threshold);
        context.Session.GetString("Threshold");
    }
}