c# - 如何通过更改同一 ListView 行中的下拉列表项来更新文本框中的文本

Question

我有一个带有 ListView 的 asp.net 页面。 I want automatically change the text of an textbox when a certain value in a dropdownlist of the same listview- row is selected.如何触发事件并更改与下拉列表同一行的 textbox.text？

Answer 1

您可以通过将 sender 的 NamingContainer 转换回 ListView DataItem 并使用 FindConrol 定位 TextBox 来完成此操作。

<asp:ListView ID="ListView1" runat="server">
    <ItemTemplate>

        <asp:DropDownList ID="DropDownList1" runat="server" 
           OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged" AutoPostBack="true">
            <asp:ListItem>Item A</asp:ListItem>
            <asp:ListItem>Item B</asp:ListItem>
            <asp:ListItem>Item C</asp:ListItem>
        </asp:DropDownList>

        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

    </ItemTemplate>
</asp:ListView>

代码隐藏。

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
    //cast the sender back to a dropdownlist
    DropDownList ddl = sender as DropDownList;

    //get the current listview dataitem from the dropdownlist namingcontainer
    ListViewDataItem item = ddl.NamingContainer as ListViewDataItem;

    //find the textbox in the item with findcontrol
    TextBox tb = item.FindControl("TextBox1") as TextBox;

    //set the text
    tb.Text = ddl.SelectedValue;
}