Question

TVirtualStringTree behaves by default if it is focused – it will scroll on mouse wheel even if mouse is not over control (except if it is over another TVirtualStringTree).

Is there a quick and elegant way to disable this behaviour?

I already did this with OnMouseWheel event and checking with PtInRect if Mouse.CursorPos if it is over a control but I have a feeling that there is a better way to do the same because this way I’d have to define a new event for each TreeView I add and also handle when to focus/unfocus the control so I hope there must be a better way to disable this.

So to be clear, I want mousewheel function to work as usual, but only when mouse is over VirtualTreeView.

Answer 1

Drop down a TApplicationEvents control to the form

in TApplicationEvents onMessage

 procedure TForm5.ApplicationEvents1Message(var Msg: tagMSG; var Handled: Boolean);
 var
  pnt: TPoint;
  ctrl: TWinControl;
 begin
  if Msg.message = WM_MOUSEWHEEL then
  begin
    if not GetCursorPos(pnt) then Exit;
    ctrl := FindVCLWindow(pnt);
    if Assigned(ctrl) then
      Msg.hwnd := ctrl.Handle;
  end;
 end;