ASP.NET MVC How to avoid static variables?

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.