資料庫連結失敗!<br><br>SELECT ER_Bank, ER_CashBuy, ER_CashSale, ER_CashDiff, ER_SpotBuy, ER_SpotSale, ER_SpotDiff FROM ExchangeRate WHERE ER_Currency = 21 ORDER BY ER_Bank<br><br>System.InvalidCastException: Object cannot be cast from DBNull to other types.
   at System.DBNull.System.IConvertible.ToInt32(IFormatProvider provider)
   at System.Convert.ToInt32(Object value, IFormatProvider provider)
   at MySql.Data.MySqlClient.Driver.LoadCharacterSets()
   at MySql.Data.MySqlClient.Driver.Configure(MySqlConnection connection)
   at MySql.Data.MySqlClient.NativeDriver.Configure(MySqlConnection conn)
   at MySql.Data.MySqlClient.MySqlConnection.Open()
   at ccioo.Data.DB_MySQL.ExecuteReader(String myQuery)