AppDomain卷影副本 - 加载/卸载动态加载的Dll

AppDomain appDomain = AppDomain.CreateDomain("DllDomain");
Assembly a = appDomain.Load(fileName);
//Assembly a = Assembly.LoadFrom(fileName);
objType = a.GetType(className);
obj = a.CreateInstance(className);
object[] args = new object[1];
args[0]=(object) "test";
object ret = objType.InvokeMember("Perform", BindingFlags.Default | BindingFlags.InvokeMethod, null, obj, args);
string output = ret.ToString();
obj = null;
AppDomain.Unload(appDomain);