Ich habe für sowas das hier
Delphi-Quellcode:
procedure CheckFormPosition(const CustomForm: TCustomForm);
begin
if (Screen.MonitorFromWindow(CustomForm.Handle, mdNull) = nil) and (Screen.MonitorCount > 0) then
begin
CustomForm.Top := (Screen.Monitors[0].Height - CustomForm.Height) div 2;
CustomForm.Left := (Screen.Monitors[0].Width - CustomForm.Width) div 2;
end;
end;