public abstract class ServiceContext : IDisposable
    {
        /// <summary>
        /// 數(shù)據(jù)庫(kù)操作上下文
        /// </summary>
        public readonly DefaultDbContext DbContext = new DefaultDbContext();

        /// <summary>
        /// 緩存組件
        /// </summary>
        public CacheContext CacheContext { get; private set; }

        /// <summary>
        /// 動(dòng)態(tài)設(shè)置緩存對(duì)象的新實(shí)例
        /// </summary>
        /// <param name="cacheContext">緩存實(shí)例對(duì)象</param>
        public void SetCacheInstance(CacheContext cacheContext)
        {
            //先釋放現(xiàn)有的緩存組件
            if (CacheContext != null)
            {
                CacheContext.Dispose();
                CacheContext = null;
            }

            //初始化緩存組件新的實(shí)例
            CacheContext = cacheContext;
        }

        public void SetCacheInstance(Type cacheContextType)
        {
            if (cacheContextType == null)
            {
                throw new ArgumentNullException("cacheContextType");
            }

            if (!typeof(CacheContext).IsAssignableFrom(cacheContextType))
            {
                throw new ArgumentException(
                    string.Format(CultureInfo.CurrentCulture, "該類型 {0} 必須繼承自抽象類CacheContext", cacheContextType),
                    "cacheContextType");
            }

            try
            {
                CacheContext = Activator.CreateInstance(cacheContextType) as CacheContext;
            }
            catch (Exception ex)
           {
                throw new InvalidOperationException(
                        String.Format(
                            CultureInfo.CurrentCulture,
                            "創(chuàng)建抽象類 CacheContext 的實(shí)例 {0} 失敗",
                            cacheContextType),
                        ex);
            }
        }

        public void Dispose()
        {
            if (DbContext != null)
            {
                DbContext.Dispose();
            }

            if (CacheContext != null)
            {
                CacheContext.Dispose();
            }
        }
    }