How to get Item index in FMX.TreeView with CheckBoxes if CheckBox was changed?

Question

I'm trying to use FMX.TreeView with CheckBoxes, but can't find a way how to identify item, which fired TreeViewChangeCheck event.

All solutions I found were about VCL.ComCtrls TreeView with TTreeNode class, but I am using FMX.TreeView.

Can anybody help me? Thanks.

Answer 1

The OnChangeCheck event is of class TNotifyEvent. Its Sender: TObject parameter tells you who triggered the event. For example, the following code

procedure TForm19.TreeView1ChangeCheck(Sender: TObject);
begin
  ShowMessage(Sender.ToString);
end;

might show TTreeViewItem 'TreeViewItem5'

Or, if you want to change a property of that item,

procedure TForm19.TreeView1ChangeCheck(Sender: TObject);
begin
  if Sender is TTreeViewItem then
    if TTreeViewItem(Sender).IsChecked then
      TTreeViewItem(Sender).Text := 'Checked'
    else
      TTreeViewItem(Sender).Text := 'Not checked';
end;

Or, if you really want the index of the item:

  ShowMessage(IntToStr((Sender as TTreeViewItem).Index));