Determine if a control is showing-CodePudding

Lets say I have a pagecontrol with two tabsheet. There is a button on the first sheet but the active sheet is the second. In this case how can I determine if that button is showing (e.g. visible for the user) or not? I tried the button's Showing property, but for some reason its always True.

update: for the clarification I don't mind if the control is outside of the desktop's visible area or covered by any other application's window.

CodePudding user response：

You can simply go up in the VCL tree until you find an element which isn't visible, or you have no other parent to check.

function IsVisible(Obj:TWinControl):boolean;
begin
  Result:=Obj.Visible;
  if not Obj.Visible then Exit;

  while Obj.HasParent do
  begin
    Obj:=Obj.Parent;
    Result:=Obj.Visible;
    if not Result then Exit;
  end;
end;