How to base on a given string class name to create the class' instance

// Assume the className that passed in is the runBase class name.

object CreateInstanceBaseClassName(str _className)
{
Object dialog;
DictClass DictClass;
Object classInstance;
;
DictClass = new Dictclass(classname2id(_className));
classInstance = dictclass.makeObject();
classInstance.init();
classInstance.method1; // method in the _className class, must make sure it existed
if (classInstance.prompt())
classInstance.run();
return classInstance;
}