asp.net下拉列表选定值显示在网格视图内的文本框中

<asp:DropDownList ID="ddlOptions" runat="server" AutoPostBack="True" OnSelectedIndexChanged="ddlOptions_SelectedIndexChanged">
    <asp:ListItem Text="Option 1" Value="1"></asp:ListItem>
    <asp:ListItem Text="Option 2" Value="2"></asp:ListItem>
    <asp:ListItem Text="Option 3" Value="3"></asp:ListItem>
</asp:DropDownList>

<asp:GridView ID="gvData" runat="server">
    <Columns>
        <asp:TemplateField>
            <ItemTemplate>
                <asp:TextBox ID="txtValue" runat="server"></asp:TextBox>
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

protected void ddlOptions_SelectedIndexChanged(object sender, EventArgs e)
{
    DropDownList ddl = (DropDownList)sender;
    GridViewRow row = (GridViewRow)ddl.Parent.Parent;
    TextBox txtValue = (TextBox)row.FindControl("txtValue");
    txtValue.Text = ddl.SelectedValue;
}