public bool Authorize(int userId, string schemaId, string actionId)
		{
			if(string.IsNullOrWhiteSpace(schemaId))
				throw new ArgumentNullException("schemaId");

			if(string.IsNullOrWhiteSpace(actionId))
				throw new ArgumentNullException("actionId");

			//创建授权事件参数
			var args = new AuthorizationEventArgs(userId, schemaId, actionId, true);

			//激发“Authorizing”事件
			this.OnAuthorizing(args);

			//如果时间参数指定的验证结果为失败,则直接返回失败
			if(!args.IsAuthorized)
				return false;

			//获取指定的安全凭证对应的有效的授权状态集
			var states = this.GetAuthorizedStates(userId, MemberType.User);

			args.IsAuthorized = states != null && states.Any(state => string.Equals(state.SchemaId, schemaId, StringComparison.OrdinalIgnoreCase) &&
			                                             string.Equals(state.ActionId, actionId, StringComparison.OrdinalIgnoreCase));

			//激发“Authorized”事件
			this.OnAuthorized(args);

			//返回最终的验证结果
			return args.IsAuthorized;
		}
		protected virtual void OnAuthorized(AuthorizationEventArgs args)
		{
			var handler = this.Authorized;

			if(handler != null)
				handler(this, args);
		}