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Lazarus Pascal - How to add properties or extra data to TTreenode? (used in TTreeview)
Delphi, Lazarus, Free Pascal
August 6, 2022 8:07 AM
So when having a list in a TreeView, how do I add more properties to each node?
I found it surprisingly easy to create my own TreeNode variant ...
TMyTreeNode = class(TTreeNode)
property ANewProperty: String read fANewProperty write fANewProperty;
No to make sure this new type is being used when adding a new node/row to the Treeview, we need to make sure the onCreateNodeClass sets our new type:
procedure TForm1.TreeView1CreateNodeClass(Sender: TCustomTreeView; var NodeClass: TTreeNodeClass);
NodeClass := TMyTreeNode;
Now when accessing the data, you will need to cast the proper type though:
TMyTreeNode(TreeView1.Selected).ANewProperty := 'some text';
Note that you not have to limit this to a simpel string - I've used this with large records as well and it works great.