[C#] Generic Singleton Pattern

這是一個利用泛型實踐單例的範例

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

namespace DesignPattern
{
   public class TSingleton<T> where T : class
   {
       static object SyncRoot = new object();
       static T instance;
       public static readonly Type[] EmptyTypes = new Type[0];
       public static T Instance
       {
           get
           {
               if (instance == null)
               {
                   lock (SyncRoot)
                   {
                       if (instance == null)
                       {
                           ConstructorInfo ci = typeof(T).GetConstructor(BindingFlags.NonPublic | BindingFlags.Instance, null, EmptyTypes, null);
                           if (ci == null) { throw new InvalidOperationException("class must contain a private constructor"); }
                           instance = (T)ci.Invoke(null);
                           //instance = Activator.CreateInstance(typeof(T)) as T;
                       }
                   }
               }
               return instance;
           }
       }
   }
}