try
  StrToInt(Sender.AsString);
except
  on E: Exception do
    raise Exception.Create('請輸入整數');
end;

begin
  //比如"箱數"欄位位于資料欄位的第三順位﹐即SelectedIndex屬性值為2
  if DBGrid1.SelectedIndex = 2 then
    begin
      if Not (Key In ['0'..'9', #8]) then
      //#8指的是后退鍵
        Key := #0;
    end;
end;

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