sorry i say not clear. question 1. currency exchange rate talbe( Currid currid2 exrate) .
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HKD USD 7.8
case 1. if current entry HKD in currid is ok , but if entry HKD in currid and USD in currid2 , then will pop message, because already exits.
case 2. if current entry HKD in currid is ok, but if entry HKD in currid and HKD in currid2, then also pop messge,because can't convert rate.


question 2.
Why i use DataGridViewComboBoxColumn control, i can't use e.FormattedValue in dg.CellValidating to checking,
even i select the HKD , then i set break point to see, it also e.FormattedValue =" " .
How to check DataGridViewComboBoxColumn value.

How can i check this 2 question in dg.CellValidating method.

Thank you ~~~