C# 2013, Deduct total amount upto paying everytime

Question

I need to load datasource from database tabel to show on datagridview and in the datagrideview I have colum Col1 called Pay/time and col2 called amount. I want to minus Col2 to Col1 in Row0 and Col2 in row2 would be the sum of row0 or:

 this code just working when the datagridview load or fill

 

 

Col1    Col2

1,000 - 10,000 = 9,000

1,000 - 9,000  = 8,000

1,000- 8,000  = 7,000

 

1,000 - n

1,000 -0

0

 

something like that. I do not know how to say in English well but I hope understand how to do it

 

I just can do Like

 

Col1         Col2

1,000       10,000

1,000       10,000

1,000       10,000

 

it keeps the same amount

 

Advance thanks

Agently need it.