How to Display "Bold" Items in the TTreeView component

The TTreeView Delphi component displays a hierarchical list of items, such as the headings in a document.

By default (Windows drawing), all items (tree nodes) of a tree view share the same font styling. If you want to have each item of a tree view to look differently you would need to include some special owner drawing techniques.

If you only want to apply *bold* to some tree items (their Captions), you can use a "special" (defined in the CommCtrl.pas unit) TreeView API.

Here's a simple trick to display some of the tree items in bold:

uses CommCtrl, ...;

procedure BoldTreeNode(treeNode: TTreeNode; Value: Boolean) ;
var
   treeItem: TTVItem;
begin
   if not Assigned(treeNode) then Exit;

   with treeItem do
   begin
     hItem := treeNode.ItemId;
     stateMask := TVIS_BOLD;
     mask := TVIF_HANDLE or TVIF_STATE;
     if Value then
       state := TVIS_BOLD
     else
       state := 0;
   end;

   TreeView_SetItem(treeNode.Handle, treeItem) ;
end;

//Usage
   BoldTreeNode(TreeView1.Items[1], True) ;
   BoldTreeNode(TreeView1.Items[6], True) ;

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