Question

【C#】看看这段计算总价的代码哪里出了问题？每次的计算总额总是上一次商品的单价，而不是总数。

private void TotalPrice(DataTable cart)
{
foreach (DataRow dr in cart.Rows)
{
double Total = 0;
Total += Convert.ToDouble(dr["UnitPrice"].ToString()) * Convert.ToDouble(dr["Number"].ToString());
this.ltrSalary.Text = Total.ToString();
}
}

Answer 1

private void TotalPrice(DataTable cart)
{//应该放在这里double Total = 0;
foreach (DataRow dr in cart.Rows)
{
Total += Convert.ToDouble(dr["UnitPrice"].ToString()) * Convert.ToDouble(dr["Number"].ToString());
this.ltrSalary.Text = Total.ToString();
}
}

Answer 2

"double Total = 0"每次调用都置0,得到的数据肯定就是最后运算的数据了

Answer 3

double Total = 0 拿到循环外面去 在里面它每一次都被重新赋值为0了