Hi All,

I have tried to calculate a calculation but I not very sure where I should place the format. I want the TA appeal in txtAmount.Text when the Form Load and GT do the calculation after key in ST.

eg:
I have this:

UP = txtUnitPrice.Text
QT = txtQty.Text
TA = txtAmount.Text
ST = txtSalesTax.Text
GT = txtGrandTotal.Text

TA = QT * UP
and
if ST have value then
GT = TA + ST
Else
GT = TA

What should I do when I face this problem??
Thank you.

Annie