An object reference is required for the non-static field, method, or property

[Rach26]

Hello I am currently developing my masters project and am relativly new to C#
I am having a problem with my Cache. In settings.settin gs I have placed the following after my connection setting:

DefaultCacheDur ation_Day Int Application 1
DefaultCacheDur ation_Hours Int Application 0
DefaultCacheDur ation_Minutes Int Application 0

I then have a cache.cs:

using System;
using System.Collections;
using System.Collections.Generic;
using System.Web;
using System.Web.Caching;
using Forestry.SchoolLibrary.Properties;
 
namespace Forestry.SchoolLibrary.Impl
{
    public class Cache
    {
        private static System.Web.Caching.Cache cache;
        private static TimeSpan timeSpan = new TimeSpan(
            Settings.Default.DefaultCacheDuration_Days,
            Settings.Default.DefaultCacheDuration_Hours,
            Settings.Default.DefaultCacheDuration_Minutes, 0);
 
        static Cache()
        {
            cache = HttpContext.Current.Cache;
        }
 
        public static object Get(string cache_key)
        {
            return cache.Get(cache_key);
        }
 
        public static List<string> GetCacheKeys()
        {
            List<string> keys = new List<string>();
            IDictionaryEnumerator ca = cache.GetEnumerator();
            while (ca.MoveNext())
            {
                keys.Add(ca.Key.ToString());
            }
            return keys;
        }
 
        public static void Set(string cache_key, object cache_object)
        {
            Set(cache_key, cache_object, timeSpan);
        }
 
        public static void Set(string cache_key, object cache_object, DateTime expiration)
        {
            Set(cache_key, cache_object, expiration, CacheItemPriority.Normal);
        }
 
        public static void Set(string cache_key, object cache_object, TimeSpan expiration)
        {
            Set(cache_key, cache_object, expiration, CacheItemPriority.Normal);
        }
 
        public static void Set(string cache_key, object cache_object, DateTime expiration, CacheItemPriority priority)
        {
            cache.Insert(cache_key, cache_object, null, expiration, System.Web.Caching.Cache.NoSlidingExpiration, priority, null);
        }
 
        public static void Set(string cache_key, object cache_object, TimeSpan expiration, CacheItemPriority priority)
        {
            cache.Insert(cache_key, cache_object, null, System.Web.Caching.Cache.NoAbsoluteExpiration, expiration, priority, null);
        }
 
        public static void Delete(string cache_key)
        {
            if (Exists(cache_key))
                cache.Remove(cache_key);
        }
 
        public static bool Exists(string cache_key)
        {
            if (cache[cache_key] != null)
                return true;
            else
                return false;
        }
 
        public static void Flush()
        {
            foreach (string s in GetCacheKeys())
            {
                Delete(s);
            }
        }
    }
}

My error message is An object reference is required for the non-static field, method, or property 'Forestry.Schoo lLibrary.Proper ties.Settings.D efaultCacheDura tion_Hours.get'

and this appears in my connection.cs which is as follows:

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Data.Linq;
using System.Text;
using System.Xml;
using Forestry.SchoolLibrary.Domain;
using Forestry.SchoolLibrary.Properties;
 
namespace Forestry.SchoolLibrary.DataAccess.Impl
{
   public class Connection
    {
        public SchoolDataContext GetContext()
        {
            string connString = "";
            try
            {
                XmlDocument doc = new XmlDocument();
                doc.Load("ConnectionStringToUse.xml");
 
                XmlNodeList xnl = doc.GetElementsByTagName("environment");
                XmlElement xe = (XmlElement)xnl[0];
 
                switch (xe.InnerText.ToString().ToLower())
                {
                    case "local":
                        connString = Settings.DefaultCacheDuration_Hours.SchoolConnectionStringLocal;
                        break;
 
                    case "development":
                        connString = Settings.DefaultCacheDuration_Hours.SchoolConnectionStringDevelopment;
                        break;
 
                    case "production":
                        connString = Settings.DefaultCacheDuration_Hours.SchoolConnectionStringProduction;
                        break;
 
                    default:
                        throw new Exception("No connection string defined in app.config!");
                }
            }
            catch
            {
                connString = Settings.DefaultCacheDuration_Hours.SchoolConnectionStringLocal;
            }
 
            SchoolDataContext fdc = new SchoolDataContext(connString);
            return fdc;
        }
    }
}

I'm not sure if I have provided all the relevant information, but if anyone could help me figure this out it would be greatly appreciated
many thanks
Rachel

[tlhintoq]

In general terms:

Any object or method marked 'static' means you only have one of them.
You cannot create multiple instances of such a method or object.

Any object or method NOT marked 'static' means you *have* to make an instance of it in order to use it.

Thus you cannot call a static method like you would a non-static method, and vice-versa

When you run this in debug, and Visual Studio stops on a line and highlights for this error... that should show you where the error occurs. At that point you are trying to get an *instance* of something that has been labeled static. And you can't do that. That's what the error is saying: You have a field, or method or property that isn't static ("for the non-static feild, property or method"), that needs a instance of an object