Question

我有以下asp.net代码

<asp:DropDownList ID="cat_points_total" runat="server" DataSourceID="semester1" 
DataTextField="cats_points_total" DataValueField="cats_points_total" 
Visible="true"></asp:DropDownList>

<asp:CheckBoxList ID="module_semester_1" runat="server" DataSourceID="semester1"
 DataTextField="module_name" DataValueField="cats_points"></asp:CheckBoxList>

<asp:Label ID="sem_1_fb" runat="server" Text=""></asp:Label>

<asp:Button ID="sem_1_cat" runat="server" Text="Test" OnClick="sem_1_cat_Click" />

用户可以从复选框列表中选择多个选项。 DataValueField的{{1}}是一个int。在这种情况下，它们的值都为cats_points。 20控件中找到的cats_points_total是另一个int值，用于链接用户可以选择的最大总数。在这种情况下，它是DropDownList。

然后我有以下C＃

目前，无论我在protected void sem_1_cat_Click(object sender, EventArgs e) { for (int i = 0; i < module_semester_1.Items.Count; i++) { if (module_semester_1.Items[i].Selected) { string value = module_semester_1.Items[i].Value; int cattotal; cattotal = Convert.ToInt32(cat_points_total.SelectedValue); cattotal = int.Parse(cat_points_total.SelectedValue); int catselected; catselected = Convert.ToInt32(value); catselected = int.Parse(value); int catcalc; catcalc = cattotal - catselected; sem_1_fb.Visible = true; sem_1_fb.Text = "cattotal =" + cattotal + " catselected =" + catselected + " catcalc =" + catcalc + "."; } } }中做出多少选择，我都会获得CheckBoxList的输出

我选择2个值的预期结果，每个值的值为20;

cattotal =120 catselected =20 catcalc =100.

在当前时间，除了cattotal =120 catselected =40 catcalc =100.之外，一切似乎都有效，计算CheckBoxList控件的值总和。任何帮助将不胜感激。

Answer 1

为什么要解析值两次（即使用Convert.ToInt32()和int.Parse()）？只做一个或另一个。无论如何，将变量声明移出循环并使用catselected添加到+=，否则您将使用每个新循环覆盖先前的值。

试试这个：

protected void sem_1_cat_Click(object sender, EventArgs e)
{
    int catselected = 0;

    for (int i = 0; i < module_semester_1.Items.Count; i++)
    {
        if (module_semester_1.Items[i].Selected)
        {
            string value = module_semester_1.Items[i].Value;
            catselected += int.Parse(value);
        }
    }
    int cattotal = int.Parse(cat_points_total.SelectedValue);
    int catcalc = cattotal - catselected;

    sem_1_fb.Visible = true;
    sem_1_fb.Text = "cattotal =" + cattotal + " catselected =" +
                    catselected + " catcalc =" + catcalc + ".";
}

使用Datasource计算asp：CheckBoxList中多个值的总和

1 个答案: