处理aspx页面中用户控制下拉列表选择的索引更改事件

Question

我已经创建了用户控件并在aspx代码中添加了相同的控件。我想处理选择的索引更改事件在aspx页面下拉列表。请帮我做这件事。

<div class="row">
    <div class="col-lg-2">
        <asp:Label ID="lbl_parent" runat="server" Text="Parent Node" CssClass="control-label"></asp:Label>
    </div>
    <div class="col-lg-6">
        <asp:DropDownList ID="ddl_parent" runat="server" CssClass="form-control" AutoPostBack="true">
        </asp:DropDownList>
    </div>
</div>
phContactDetails.Controls.Add(LoadControl("~/UserControl/WUC_DisLabelControl.ascx"));
foreach (var control in phContactDetails.Controls)
            {
                var usercontrol = control as WUC_DisLabelControl;
                DropDownList ddl_parenrt = ((DropDownList)usercontrol.FindControl("ddl_parent"));
                ddl_parenrt.SelectedIndexChanged += new EventHandler(ddlparent_SelectedIndexChanged);
}
protected void ddlparent_SelectedIndexChanged(object sender, EventArgs e)
        {
            throw new NotImplementedException(); //Not Firing 
        }

Answer 1

您没有在下拉列表中添加SelectedIndexChanged事件。

下拉菜单中添加SelectedIndexChanged="ddlparent_SelectedIndexChanged"

<asp:DropDownList ID="ddl_parent" runat="server" CssClass="form-control" AutoPostBack="true" OnSelectedIndexChanged="ddlparent_SelectedIndexChanged">
</asp:DropDownList>