Breast Enhancement Options Is Celexa An Maoi Inhibitor Pain Pill Neurontin Melatonin And Tylenol Cymbalta Causeing Memory Loss Purim Recipes Index Adult Dose For Zyrtec Chitosan In Agricultural Hgh G Gorden Liddy Missouri Harassment Defense Lexapro Withdrawing From Trazodone Paxil And Xanax Levlen Ed Improved Skin Hgh Releaser Therapy Hgh Product Melatonin And Liver Issues Singulair Manufacturer Rebates Colitis And Zelnorm Chances Of Pregnancy During Clomid Breast Enhancement Cream Mirifem How Is Luvox Different From Zoloft Generic Zantac Lamictal And Depresion Generic Name For Hytrin What Is Differin Good For Melatonin Toxicity Smart Burn With Hoodia Testimonials Propecia Reversing Miniaturization Temples Viagra Race Car Screen Saver Small Breast Enhancement Gum Cipro Vs Coumadin Lisinopril Hctz Generic Picture Aleve Drops Blood Count Dont Use Prednisone Information On Paxil Lasix Induced Metabolic Alkalosis Site About Tramadol Dip Effexor Zr Side Effects Prednisone Side Effects Brite Smile Whitening Viagra Us Drugs Stors Coral Calcium Removethis The Brite Box Ford Ranger Medrol Dos Identify Somas Prednisone Muscle-wasting Dog Purim What Is Geodon Iv Maximum Dosing Does Hair Thicken With Rogaine Is Elavil A Narcotic Hpt And Cozaar David Chu Soma

Helpers in MonoRail provide a very convenient way to extend your presentation logic. However, it’s important to note that MonoRail will initialize helper instances for a controller before the session state has been created for the request. The implication of not having session state when helpers are initialized is that you cannot check session state in a helper’s constructor. Consider the following:

[Helper(typeof(SomeHelper))]
public class SomeController : Controller
{
       public void SomeAction() {}
}

public class SomeHelper: AbstractHelper
    {
        public SomeHelper()
        {
            if (HttpContext.Current.Session["SOME_KEY"] != null)
                doSomething();
        }
}

When the request for /SomeController/SomeAction.rails is processed, the SomeHelper instance will be created. When the constructor code executes, a null reference exception will occur when attempting to access an item in session. The obvious implication is that any initialization code that is session state dependent cannot be in the constructor. The solution I’ve used is to create an initialize method that is called from any method requiring the setup routine.

Update 2008-02-21 - this issue cropped up with controllers too. Session is not created at the time controllers are instantiated either. Avoid constructors that check session state.