How to access the TempData in the startup.cs file?

Question

I have a Middleware in the startup.cs file (Razor Pages) and want to check whether a value exists in the TempData, but I cannot find a way to access the TempData. Am I heading towards a bad practice? If so, how could I read a runtime-produced value in my Middleware?

Answer 1

You can try to use ITempDataDictionaryFactory,Here is a demo:

Middleware:

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            app.Use(async (context, next) =>
            {
                ITempDataDictionaryFactory factory = context.RequestServices.GetService(typeof(ITempDataDictionaryFactory)) as ITempDataDictionaryFactory;
                ITempDataDictionary tempData = factory.GetTempData(context);
                //get or set data in tempData
                var TestData=tempData["TestData"];
                // Do work that doesn't write to the Response.
                await next.Invoke();
                // Do logging or other work that doesn't write to the Response.
            });
       }

HomeController:

public class HomeController : Controller
    {
        
        public IActionResult Index()
        {
            TempData["TestData"] = "test";
            return View();
        }

       
    }

result: