下拉列表事件不触发?为什么 [英] dropdown list event is not firing ? why

问题描述

有人知道吗?


下拉列表事件不触发?为什么
编码:

Can Anyone know?


dropdown list event is not firing ? why
coding:

protected void ddlplace_SelectedIndexChanged(object sender, EventArgs e)
    {

        if (ddlplace.SelectedIndex > 0)
        {
            float delivervalue, tax, shipping;
            string deliveryarea = ddlplace.SelectedItem.Value.ToString();
            delivervalue = dal.getdelivervalue(deliveryarea);
            lbldp.Text = delivervalue.ToString();
            tax = dal.gettax(deliveryarea);
            lbltax.Text = tax.ToString();
            shipping = dal.getshipping(deliveryarea);
            lblship.Text = shipping.ToString();
        }

    }

推荐答案

其他几种情况(Autopostback=True除外)

ASP.NET:错误:DropDownList OnSelectedIndexChanged事件未触发 [在页面加载时检测DropDownList SelectedIndexChanged [

Here other couple of cases(other than Autopostback=True)

ASP.NET: Error: DropDownList OnSelectedIndexChanged Event Not Firing[^]
also check this
Detect DropDownList SelectedIndexChanged on Page Load[^]

将autopostback属性设置为true

set autopostback property to true of dropdown list.

首先在aspx中检查是否具有OnSelectedIndexChanged以及是否设置了autopostback = true

如:

first check in aspx whether you are having OnSelectedIndexChanged or not and whether you set autopostback=true

as:

<asp:DropDownList ID="ddlCity" runat="server" CssClass="dropdownlist" OnSelectedIndexChanged="ddlCity_SelectedIndexChanged"

                                                                            AutoPostBack="true">
                                                                            <asp:ListItem Value="0">--select--

或确保下拉绑定代码位于if(！Page.IsPostBack)块中

or make sure that dropdown binding code is in if(!Page.IsPostBack) block

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