It is possible to add ListB PurchaseOrderHeader and Supplier into List A PurchaseOrderHeader and Supplier? I had try join, concat, but it see like not working well
POLine.
List A
List B
Edit
Sorry for forgot to add code
POLine.Select(c => c.PurchaseOrderHeader).Concat(DataFromParent.Select(c=>c.PurchaseOrderHeader));
Update
It is possible to make it?
List A PurchaseOrderHeader = null, PurchaseOrderLine =some value , Supplier = null
List B only have PurchaseorderLine = null,
can anyhow merge it to make it
List A PurchaseOrderheader = List B PurchaseOrderHeader, List A PurchaseOrderLine remain, and List A Supplier = List B Supplier?