分享一個單例模型類Singleton代碼

相關代碼：

using System;
using System.Collections.Generic;
using System.Text;

namespace Pixysoft.DesignPattern
{
    public class Singleton<T>
    {
        private Dictionary<string, T> dict = new Dictionary<string, T>();

        private string _id = null;

        private static volatile object instance;

        private static object syncRoot = new Object();

        public static T Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (syncRoot)
                    {
                        instance = Activator.CreateInstance(typeof(T));
                    }
                }

                return (T)instance;

            }
        }

        public T this[string id]
        {
            get
            {
                //如果是null，表示自己，則直接返回Instance

                if (string.IsNullOrEmpty(id))
                    return Instance;

                id = id.Trim().ToUpper();

                lock (syncRoot)
                {
                    if (dict.ContainsKey(id))
                        return dict[id];

                    object i = Activator.CreateInstance(typeof<