Session in ASP.NET WebForm is cleared after authenticated by Entra ID with CookieAuthentication and WsFederationAuthentication about aspnetkatana

[Tratcher]

@yooontheearth unfortunately this product is not under active development. We may consider PRs, but don't expect feature work or investigations at this point. I recommend StackOverflow for this class of question.

[yooontheearth]

@Tratcher thank you for letting me know about it. I'll ask at StackOverflow then.

Edit
I could make Session work as using PreApplicationStartMethod and HttpModule instead of doing stuff in Global.asax. I'll share the code for those who might need it.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Net;
using System.Resources;
using System.Web;
using System.Web.Http;
using System.Web.Routing;
using System.Web.UI;
using Newtonsoft.Json.Serialization;
using System.Web.SessionState;

[assembly: PreApplicationStartMethod(typeof(AppStartup), "Initialize")]

namespace Test
{
    public static class AppStartup
    {
        // Equivalent to protected void Application_Start(object sender, EventArgs e) in Global.asax
        public static void Initialize()
        {
            // Do something for start app if you want

            // Register a module to do something on every request
            HttpApplication.RegisterModule(typeof(AppHttpModule));
        }
    }

    internal sealed class AppHttpModule : IHttpModule
    {
        public void Init(HttpApplication context)
        {
            context.PostAuthorizeRequest += Context_PostAuthorizeRequest;   
        }

        private void Context_PostAuthorizeRequest(object sender, EventArgs e)
        {
			// Enable session if it's for web api
            if (IsWebApiRequest())
            {
                System.Web.HttpContext.Current.SetSessionStateBehavior(SessionStateBehavior.Required);
            }
        }

        private bool IsWebApiRequest()
        {
            return System.Web.HttpContext.Current.Request.AppRelativeCurrentExecutionFilePath.StartsWith("~/api");
        }

        public void Dispose()
        {
        }
    }
}