在ASP.NET MVC5上设置值之后，每个请求中的静态属性始终为null

Question

I have a static class and static property

 public static class Test
 {
     public static string Tests { get; set; }
 }

Now the problem is, I have a Action in a Controller

public ActionResult SomeActionInController(){
         ``              ``
     //  this place always execute in every request
     if (null == Test.Tests)
          Test.Tests = "some value";
         ``              ``
}

But I will get null in every requests, not local debug, only on the server .

I saw so many people said : Static property value will keeping on whole application domain , But why this is happening now ? Is there any way to fixed it? Thank you.

My Server use IIS 8.5 with Windows Server 2012 R2

Update1

There is no static constructor in the static class.

if I send request to the Action, the null will happen every time, because I can see it use log4net .

I already disable Idle time out and free time out, all set to 0 . So there is no recycle problem.

This is my Global.asax:

public class MvcApplication : System.Web.HttpApplication
    {
        private readonly log4net.ILog log = log4net.LogManager.GetLogger(typeof(MvcApplication));

        protected void Application_Start()
        {
            Elmah.Mvc.Bootstrap.Initialize();
            AreaRegistration.RegisterAllAreas();
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);


            // Setting log4net
            log4net.Config.XmlConfigurator.ConfigureAndWatch(new System.IO.FileInfo(Server.MapPath("~/log4net.config")));


            // Only keep Razor
            ViewEngines.Engines.Clear();
            ViewEngines.Engines.Add(new RazorViewEngine());



            System.Threading.Tasks.Task.Factory.StartNew(new Action(() =>
            {
                try
                {
                    System.Threading.Thread.Sleep(1000 * 100 * 1);

                    // Send a fake request for warm up the website, when after it recycle
                    WebClient webClient = new WebClient();
                    using (Stream stream = webClient.OpenRead(ConfigurationManager.AppSettings["InitialPath"]))
                    {
                        if (stream.CanRead)
                        {
                            log.Debug("Success warm up when recycle");
                        }
                        else
                        {
                            log.Debug("warm up failed");
                        }
                    }



                }
                catch (WebException ex)
                {
                    log.Debug(ex);
                }
                catch (Exception ex)
                {
                    log.Error(ex);
                }
            }));

        }


        /// <summary>
        /// Setting Page Language
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void Application_AcquireRequestState(object sender, EventArgs e)
        {
            if (HttpContext.Current != null && HttpContext.Current.Session != null)
            {
                if (AdminLanguage == 1)
                {
                    Thread.CurrentThread.CurrentCulture = new CultureInfo("xx-xx");
                    Thread.CurrentThread.CurrentUICulture = new CultureInfo("xx-xx");
                }
                else
                {
                    Thread.CurrentThread.CurrentCulture = new CultureInfo("xx-xx");
                    Thread.CurrentThread.CurrentUICulture = new CultureInfo("xx-xx");
                }
            }
        }


        /// <summary>
        /// Cache setting
        /// </summary>
        /// <param name="context"></param>
        /// <param name="arg"></param>
        /// <returns></returns>
        public override string GetVaryByCustomString(HttpContext context, string arg)
        {
            // cache from DevTrends.MvcDonutCaching
            if (arg == "NavStatic")
            {
                return "NavStatic=" + HttpContext.Current.Session.SessionID;
            }

            return base.GetVaryByCustomString(context, arg);
        }

    }

Update 2

I will set it every time, because I use this code, So don't worry about it.

       if (string.IsNullOrEmpty(Test.Tests))
                    {
                        log.Debug("Test: null, this time it will be setting");
                        Test.Tests = "Test";
                    }
                    else
                    {
                        log.Debug("Test: " + Test.Tests);
                    }

And on the server, The log4net will output it when every request(access the action) :

Test: null, this time it will be setting

Test: null, this time it will be setting

Test: null, this time it will be setting

Update3

For some friends advice I put some code in the Application_Start()

Test.Tests = "Test";

So now, every request it will successful get the value. But I change my code to this in Action:

if (string.IsNullOrEmpty(Test.Tests))
                        {
                            log.Debug("Test: null, this time it will be setting");
                            Test.Tests = "Test";
                        }
                        else
                        {
                            log.Debug("Test: " + Test.Tests);
                            Test.Tests = "Test3";
                            log.Debug("Now the Test new Value = " + Test.Tests);
                        }

Now every request the log4net will output like this:

Test: Test

Now the Test new Value = Test3

Test: Test

Now the Test new Value = Test3

Test: Test

Now the Test new Value = Test3

But that's not what I want . I want the static property can be read and modify in whole application domain, not only 1 time .

Answer 1

After discussion with George Stocker and Dave Becker , And keeping debug it. And finally find the problem source is: just because I create the log4net log file into the website "Bin" folder . then when every request come in, log4net write the log, and IIS detect there is some file changed, then The Application_End() will execute. all gone.

Many thanks these 2 firends.

If you has a same problem, don't every put or create any file to "Bin" folder, or trying to write it. Unless you want application destroyed you can do it :-)

Answer 2

It sounds like you want a global variable in ASP.NET MVC. Luckily your problem has already been solved with this Stack Overflow question .

Statics aren't magical. If you don't set them, they will have no value.

In your controller action, you're checking to see if it's set yet (hint: If you didn't set it already, it's not set):

if (null == Test.Tests) 
{
    Test.Tests = "some value";
}

So where are you setting Test.Tests ? If you want it to be set for each controller action, you need to be sure it's set when that controller action would run. A great place would be in your Application_Start method of your global.asax.cs:

public class MvcApplication : System.Web.HttpApplication
{

    protected void Application_Start()
    {
        Tests.Test = "This is set";
    }

}
public static class Tests 
{
    public static string Test { get; set; }
}

Controllers are instantiated on every request; the Application_Start method is called once per App Pool Recycle (or once per instantiation of the Application).

The reason your Tests.Test is null is that you never set its value.