function GetCharFromVKey(vkey: Word): string;

var

 keystate: TKeyboardState;

 retcode: Integer;

begin

 Win32Check(GetKeyboardState(keystate));

 SetLength(Result, 2);

 retcode := ToAscii(vkey,

  MapVirtualKey(vkey, 0),

  keystate, @Result[1],

  0);

 case retcode of

  0: Result := '';

  1: SetLength(Result, 1);

  2: ;

  else

  Result := '';

 end;

end;

{

Использование:

procedure TForm1.Edit1KeyDown

 (Sender: TObject; var Key: Word;

 Shift: TShiftState);

begin

 ShowMessage(GetCharFromVKey(Key));

end;

}