RE: Country region id get from logistics postal addresss
If you have LogisticsPostalAddress table buffer (which I assume, based on the information that you have shared with us), you can use all fields in that table without "passing parameter".
This works with any other table buffers as well.
But, if you have only RecId of LogisticsPostalAddress, then you indeed need to first fetch the table buffer using LogisticsPostalAddress::find() method, as suggested by BlueWang. This is also a pattern that appears everywhere in the system: if you have a key / relation to other table, you can use it to fetch the related table buffer, and then you can access any fields of the related table buffer by tableBufferName.FieldName.
These are among the first things that you should get familiar with when starting your journey as x++ developer.
Is it now clear to you? If not, could you please share full details of your business requirement, current code and possible problems / errors that you are experiencing? In general I suggest to share all this info already in your initial message whenever you post a new question. This helps you to get best possible help as soon as possible, and saves everyone's time, removing the need to guess details of your problem.
Thanks!
