it's strange, how it will run if it doesn't exist?

i try to use both option you gave to me, but no success (it's because i'm not good on this /> and I ' m ashamed to ask you further about this), anyway i use another way (not sure if this way is best way in programming), here is what i do :

first i bind all data i need from database to Datagridview1 and than i transfer whole value from Datagridview1 to Datagridview2 with "for each" looping, so whole column in Datagridview2 become unbound, after that i run whole formula i need on Datagridview2 including total, and than simply i use :

Datagridview2.Rows.Add()

to insert total in last row of Datagridview2.

thanks for your help charlie, i really appreciate that />

Where is the code for adding your unbound column to the datagrid? = i'm not using any code, i add it manually through its task/properties by select my dgv than click little arrow in top right corner >> Add Column..

why are you not adding the column to the datatable? = i use datatable to bind data from database (amount column in my database) than make it source for my dgv, after that, i use that amount to run this formula :

DataGridView1.Rows(i).Cells(0).Value = DataGridView1.Rows(i).Cells(1).Value * 2

can anyone help me please

sorry, you mean i don't have to save budget in database? and do calculation when user load the data?

ok, got it, thanks for your reply, sorry if i disturb you.