使用dynamic实现反射，并提交性能

dynamic与反射的性能比较，请参考：

http://www.cnblogs.com/cuitsl/archive/2012/01/06/2314636.html

代码如下：

string cacheInstance = ConfigurationManager.AppSettings["cachedll"];
var assembly = Assembly.Load(cacheInstance);
dynamic instance = assembly.CreateInstance(ConfigurationManager.AppSettings["cachecls"]);
return (ICache)instance;