var address = GetPropertyValue(GetPropertyValue(emp1, "Address"), "AddressLine1");

对象员工没有一个名为Address.AddressLine1"的属性，它有一个名为Address"的属性，它本身有一个名为AddressLine1"的属性.

Object Employee doesn't have a single property named "Address.AddressLine1", it has a property named "Address", which itself has a property named "AddressLine1".