delphi-make calculated field

Posted by vincent_85 on November 08, 2007

Hi,
im new to delphi, currently using delphi 6.
Im doing a purchase return management. Here's my problem:
What are the codes that i need to write to make a calculated field work?
Here is how it goes;

i have 2 cxGrids on 1 form, 1 grid on top 1 below. There's a column called 'Original Quantity' in the top grid and a column called 'Quantity' in the below cxGrid.

Then, i want to create another column in the top grid called 'Quantity left'. When i increase or decrease the number in the 'Quantity' column in the bottom grid, the amount in the 'Quantity left' column in the top grid has to show the amount left deducting from the amount in the 'Original Quantity' column. How to make it change in real time?

Unless if i click the 'OK' button in tht form, the next time i open tht form the amount will change.

I found this : htp://devexpress.com/kb=A343

but dont know how to use it. Someone help! Beginner in need!

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