การ Sum column ราคา Total ทั้งหมด ให้โชว์ใน textbox เพื่อโชว์ราคาทั้งหมด ทำยังไงครับ

int row = datagridview1.rowcount;
int money = 0;
for(int i = 0 ; i < row ; i++)
{
   int wage = convert.toint32(datagridview1.rows[i].cells[7].value.tostring());
   int amount = convert.toint32(datagridview1.rows[i].cells[5].value.tostring());
   int price = convert.toint32(datagridview1.rows[i].cells[4].value.tostring());
   int discount = convert.toint32(datagridview1.rows[i].cells[6].value.tostring());
   int total =  wage+(amount*(price-(price*discount)/100)));
   datagridview1.rows[i].cells[8].value = total.tostring();
   money = money+total;
}
textbox1.text = money.tostring();

int row = datagridview1.rowcount;
int money = 0;
for(int i = 0 ; i < row ; i++)
{
   int total = convert.toint32(datagridview1.rows[i].cells[0].value.tostring());
   money = money+total;
}
textbox1.text = money.tostring();