thousand comma separator in gridview when typing i

Question

I hope someone can help me, I need something like this : for example I type 12345 in fee column in gridview it becomes 12,345 not after the user left the column, but when she is typing,

you should suppose this is my grid

ItemNameColumn  QuantityColumn  FeeColumn

I wrote my solution here here

it workd perfectly provided that the user firstly click on the fee column, In case I fill the quantity column which is before the Fee column it does not work anymore,

Now I am not strict on the approach I used before, any method that help me to solve this problem is welcome to me,

please kindly have a glance and let me know if there is any misconception,