procedure TForm1.FormKeyPress(Sender: TObject; var Key: 
Char);
begin
  if Key = #13 then //如果是一个Enter键盘
  begin
    if not (ActiveControl is TDBGrid) then  //如果当前的控件不是TDBGrid
    begin 
       Key := #0; 
       Perform(WM_NEXTDLGCTL, 0, 0); { move to next control }
    end
    else if (ActiveControl is TDBGrid) then //在TDBGrid中
    begin
       with TDBGrid(ActiveControl) do
       begin
         if selectedindex < (fieldcount -1) then //如果不是最后一个字段
            selectedindex := selectedindex +1
         else
            selectedindex := 0;
       end;
   end;
end; 
end;

TDBGrid中用Enter仿真Tab键盘