type
TForm1 = class(TForm)
TreeView1: TTreeView;
procedure FormCreate(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.DFM}
procedure TForm1.FormCreate(Sender: TObject);
begin
SetWindowLong(TreeView1.handle,GWL_STYLE,
GetWindowLong(TreeView1.handle,GWL_STYLE) or TVS_CHECKBOXES);