>>I now have another question. Say, I have
>>

>>Application 
>>{
>>
>>  Database Database {get;set}
>>
>>   public Application(Database database)
>>   {
>>       Database = database;
>>   }
>>}
>>

>>
>>How can I from the database class set properties of the Application class (its parent in VFP terminology)?
>
>You can't. The Application class is NOT it's parent - it's just holding a reference to it. Countless other classes might also hold a reference to the same object.

Any other way around this problem? E.g. in the application class I want to keep a reference to Database class, but from Database class I want to set properties of the application class?

If, say, I add similar (or same) properties to the database class, can I somehow signal to the application class when database is setting its properties, so I can update application class properties?