[icWasya]

Ну написать вместо IN по старинке

Код:

if Not (
  ( Key >= widechar('А') and (Key <= widechar('Я')) or
  ( Key >= widechar('а') and (Key <= widechar('я')) or
  ( Key >= widechar('0') and (Key <= widechar('9')) or
  ( Key = widechar(#8))
  ) then Key:=#0;