Window Application GridView Cell Value setting

Question

In window application 

1. I have a  grid,It have 6 column(item name,min quantity,max quantity,max amount,max amount,Discount),now i want that when i select min Quantity ,max Quantity column will Disable And its Value become Zero,when i select min amount ,max amount column will Disable and its vice Versa.

2. when i enter min value in quantity then row of grid contain max value from first row.