如何更新列表框中的文本框总价格

Question

我想要做的是我将项目添加到列表框中，文本框将自动更新。我已经完成了我可以添加的价格将添加但仅限数量1如果我添加1项超过1数量将只计算数量1项目价格如何解决？

count = Math.Round(qty_of_item, 2) * (product_price)

        lblprice.Text = (" Rm " & count)
        ListBox1.Items.Add(product_name)

        ListBox4.Items.Add(product_class)
        ListBox5.Items.Add(product_size)

        ListBox3.Items.Add((" " & Math.Round(qty_of_item)))
        ListBox2.Items.Add(FormatCurrency(count))

        caculate = count

        total = 0

        Dim price As Decimal = 0
        price = total + caculate

        For i As Integer = 0 To ListBox2.Items.Count - 1 'get the item count inside listview
            price = (CDec(ListBox2.Items(0).ToString())) 'get the value of item of each item in each listbox row
            total += price 'add price into total
        Next

        txtsubtotal.Text = FormatCurrency(total)

        gst = total * 0.06
        txtgst.Text = FormatCurrency(gst)

        total_after_gst = total + gst
        txtfinaltotal.Text = FormatCurrency(total_after_gst)

    Else
        MessageBox.Show("Qty value cant be empty And only allow Integer", "Error", MessageBoxButtons.OKCancel, MessageBoxIcon.Error)

    End If

更新

这仍然无法修复

Answer 1

您必须在price

中使用caculate代替For - Next loop

For i As Integer = 0 To ListBox2.Items.Count - 1 'get the item count inside listview
    price = CDec(ListBox2.Items(i)) 'get the value of item of each item in each listbox row
    total += price 'add price into total
Next