加载程序集、查找类和调用run()方法的正确方法
class Program{
static void Main(string[] args)
{
// ... code to build dll ... not written yet ...
Assembly assembly = Assembly.LoadFile(@"C:\dyn.dll");
// don't know what or how to cast here
// looking for a better way to do next 3 lines
IRunnable r = assembly.CreateInstance("TestRunner");
if (r == null) throw new Exception("broke");
r.Run();
}}