The OnGetText event procedure definition is:
TVSTGetTextEvent = procedure (Sender: TBaseVirtualTree; Node: PVirtualNode; Column: TColumnIndex; TextType: TVSTTextType; var CellText: UnicodeString) of object;
The documentation CHM help file for this event just says:
Use other resources like the news group or the Delphi Gems message board to find a description.
I've seen some other posts on SO where they are checking for (Column < 0) in this event, so I'm curious about what this is?
FWIW, I'm trying to implement a Parent-Child tree view from database data.
You can define columns in the virtual tree's Header.Columns collection. The Column parameter that is passed to any event method where it's given, is the 0 based index of the column in this collection.
The Column parameter value can be either the 0 based index of the processed column, or NoColumn (which has internally value -1), which indicates that there is no column in your virtual tree.