2

我有一个带有下拉列表的中继器。当用户更改其索引时，我想要一个标签来更改其值。（ddlSizes 值来自 MySQL 数据库）

尺寸.aspx

<asp:DropDownList ID="ddlSizes" runat="server" AutoPostBack="True" DataSourceID="objdsSizes"  DataTextField="SizeName" DataValueField="SizeID" />

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

大小.aspx.vb

Protected Sub ddlSizes_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlSizes.SelectedIndexChanged
    lbldummy = ddlSizes.value
End Sub

但 ddlSizes.SelectedIndexChanged 无法识别。所以 的值lbldummy不会改变。

有什么建议么？谢谢你。

4

3 回答 3

7

您DropDownList需要DropDownList为RepeaterItem. 然后，您可以从中引用任何其他控件RepeaterItem

Public Sub ddlSizes_SelectedIndexChanged(sender As Object, e As EventArgs)
    Dim ddlSizes As DropDownList = DirectCast(sender, DropDownList)
    Dim ri As RepeaterItem = DirectCast(ddlSizes.Parent, RepeaterItem)
    Dim lbldummy As Label = DirectCast(ri.FindControl("lbldummy"), Label)
    lbldummy.Text = ddlSizes.SelectedValue
End Sub

然后在您的 ddlSizes DropDownList 添加 OnSelectedIndexChanged="ddlSizes_SelectedIndexChanged"并确保它设置了 AutoPostBack="True"

于 2011-05-22T19:26:59.877 回答
1

这是一个示例（C#，但很容易适应 VB.NET）。注意DdlSizes_SelectedIndexChanged我如何在里面FindControl找到相应的标签：

<%@ Page Language="C#" %>
<script type="text/c#" runat="server">
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            rep.DataSource = Enumerable.Range(1, 5);
            rep.DataBind();
        }
    }

    protected void DdlSizes_SelectedIndexChanged(object sender, EventArgs e)
    {
        var ddl = (DropDownList)sender;
        var lbl = (Label)ddl.FindControl("lbldummy");
        lbl.Text = ddl.SelectedValue;
    }
</script>
<!DOCTYPE html>
<html>
<head id="Head1" runat="server">
    <title></title>
</head>
<body>
    <form id="Form1" runat="server">
        <asp:Repeater ID="rep" runat="server">
            <ItemTemplate>
                <asp:DropDownList ID="ddlSizes" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DdlSizes_SelectedIndexChanged">
                    <asp:ListItem Value="1" Text="item 1" />
                    <asp:ListItem Value="2" Text="item 2" />
                    <asp:ListItem Value="3" Text="item 3" />
                </asp:DropDownList>
                <asp:Label ID="lbldummy" runat="server" />
            </ItemTemplate>
        </asp:Repeater>
    </form>
</body>
</html>
于 2011-05-19T16:44:40.573 回答
1

Text 可能是默认属性，但我仍然会指定它：

lbldummy.Text = ddlSizes.value

但为此，你真的不需要回发，你也可以通过 Javascript 来完成。做这样的事情：

<asp:DropDownList ID="ddlSizes" runat="server" onchange="return ddlSizes_change(this);" DataSourceID="objdsSizes"  DataTextField="SizeName" DataValueField="SizeID" />


function ddlSizes_change(dropdown)
{
     document.getElementById('<%= lbldummy.ClientID %>').innerHTML = 
         dropdown.options[myindex].value

    return true;
}
于 2011-05-19T16:40:36.340 回答