Question

我有点DUH时刻，需要一些帮助。我有一个DropDownList控件，它填充了页面加载的值和一个进行进一步操作的提交按钮。但是，单击该按钮时，DropDownList将返回值“-1”而不是所选选项。这有什么不对？

网页：

<%@ Page Language="C#" MasterPageFile="/new/MasterPageA2.master" EnableEventValidation="false" AutoEventWireup="true" CodeFile="Checkout.aspx.cs" Inherits="Common_Checkout" EnableViewState="true" %>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
<asp:UpdatePanel ID="UpdatePanel" runat="server">
<ContentTemplate>

    <asp:Label runat="server" ID="test11"></asp:Label>
    <asp:DropDownList ID="ddlbillingcountry" required="true" EnableViewState="true" runat="server"></asp:DropDownList>
    <asp:Button ID="ImageButton1" AlternateText="Proceed" OnClick="ImageButton1_Click" CausesValidation="false" runat="server" />

</ContentTemplate>
</asp:UpdatePanel>
<asp:UpdateProgress ID="UpdateProgress1" runat="server">
    <ProgressTemplate>
        <p>Loading...</p>
    </ProgressTemplate>
</asp:UpdateProgress>
</asp:Content>

代码背后：

protected void Page_Load(object sender, EventArgs e) {
  if (!IsPostBack) {
    PopulateCountry(ddlbillingcountry);
  }
}

private void PopulateCountry(DropDownList Controlname) {
    DatasetTableAdapters.CountryTableAdapter _CountryTableAdapter = new DatasetTableAdapters.CountryTableAdapter();

    Controlname.ClearSelection();
    Controlname.Items.Clear();      

    DataTable _DataTable = _CountryTableAdapter._Eco_Country_Select(); 
    Controlname.DataSource = _DataTable;
    Controlname.DataTextField = "CountryName";
    Controlname.DataValueField = "Country";
    Controlname.DataBind();
    Controlname.Items.Insert(0, new ListItem("- Select Country -", ""));
}

protected void ImageButton1_Click(object sender, EventArgs e) {
    test11.Text += "<p>clicked " + ddlbillingcountry.SelectedIndex + " - " + ddlbillingcountry.SelectedValue.ToString();

}

Answer 1

您可以将datasource属性设置为返回数据集的函数的名称。尝试datasource='<%# PopulateCountry("ddlbillingcountry") %>'但你需要更改或重载函数以将参数更改为字符串，记住设置datavaluefield和datatextfield。或者你可能想要创建一个单独的函数并调用它而不带参数。

C＃动态填充的DropDownList重置按钮OnClick

1 个答案: