ASP.NET MVC How to avoid static variables? - asp.net

Question

recently posted about questioning how unsafe static variables are, I've since discovered I need to get rid of them. But I cannot figure out how to? Was thinking a static Get() method for each class, that returns a single instance, but then that instance would have to be declared static.
So the only way to do it, is to have the instance references (for each helper, I.E user helper.cs, imagehelper.cs etc.) is to declare them as instance properties on some sort of globally accessible class? But which class? Is there something I'm missing here?
Code below of a sample class I need to change:
sing System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using Mvc.Mailer;
namespace MVCWebsite.Helpers
{
public class AppSettings
{
public static void OnAppInit()
{
//General
AppName = "MyApp";
DesktopBaseURLs = new Dictionary<string, string>();
DesktopBaseURLs.Add("dev", "localhost:50560");
DesktopBaseURLs.Add("test", "www.test.whatever.com");
DesktopBaseURLs.Add("live", "www.whatever.com");
MobileBaseURLs = new Dictionary<string, string>();
MobileBaseURLs.Add("dev", "m.local.whatever.com");
MobileBaseURLs.Add("test", "m.test.whatever.com");
MobileBaseURLs.Add("live", "m.whatever.com");
//Emails
EmailHostName = AppName + ".com"; //For the moment atleast
NoReplyEmailAddress = "no-reply#" + EmailHostName.ToLower();
SupportEmailAddress = "support#" + EmailHostName.ToLower();
ErrorEmailAddress = "errors#" + EmailHostName.ToLower();
//Resources
TempFileURL = "/content/temp/";
UserDataURL = "/content/user-content/";
ProfilePicturesURL = UserDataURL + "profile-pictures/";
var a = GlobalHelper.GetURLAsServerPath(ProfilePicturesURL);
var b = a;
}
//General
public static string AppName { get; set; }
public static Dictionary<string, string> DesktopBaseURLs;
public static Dictionary<string, string> MobileBaseURLs;
//Emails
public static string EmailHostName { get; set; }
public static string NoReplyEmailAddress { get; set; }
public static string SupportEmailAddress { get; set; }
public static string ErrorEmailAddress { get; set; }
//Resources
public static string UserDataURL { get; set; }
public static string TempFileURL { get; set; }
public static string ProfilePicturesURL { get; set; }
//Methods
public static void SetAppURL()
{
}
}
}

Answer 1

I recommend creating an interface for your AppSettings class, so that you can use it in your controllers now, and implement it in different ways as you see fit:
public interface IAppSettings
{
string AppName { get; set; }
...
}
You can then implement it immediately with your static class via a wrapper class:
public class AppSettingsWrapper : IAppSettings
{
public AppName
{
get
{
return AppSettings.AppName;
}
set
{
AppSettings.AppName = value;
}
}
...
}
Later on, you can create an implementation of IAppSettings that uses session, or cookies, or database values, or whatever. The important thing is to abstract the way you store things so that you can implement in a way that meets your needs.

Answer 2

The answer to you previous question clearly stated that the IDictionary was the only unsafe variable in your static method because it's not thread safe. You just need to store these variables differently. You don't need to get rid of all of your static variables. You just need to change IDictionary to something thread safe.
By the way, someone there makes a good coment about web.config

Answer 3

Right I think I've figured it out, they should be stored as instance variables within Global.asax.cs. This file contains your Application class which inherits from System.Web.HttpApplication. This master class is limited to one instance (of itself) per request. So if you store any references to your helpers here, you can reference them by going, MvcApplication.MyHelper.DoSomething(); Someone please correct me if this is wrong, but seems right to me. "At any single point of time, an HTTPApplication instance handles only one request, so we don't need to think about locking and unlocking of any non static members, but for static members we do require. " -from : http://www.codeproject.com/Articles/87316/A-walkthrough-to-Application-State#c