Auto multiply two column in gridview

Question

Hi Experts,

In my c# web application, I have one gridview control with the column of weight,  rating and total scoring.

When I'm entering values into the textboxes of weight and rating the total scoring textbox want to be fill automatically.

And saved into database automatically.

total scoring = weight*rating

All the Column have only Textboxes and I need the same operation for the edit mode also.

I think you guys have some draft ideas?

Hope you can help! Thanks!