<telerik:GridTemplateColumn HeaderText="Foobar">
<ItemTemplate>
<asp:DropDownList runat="server" ID="DropDownList1" AutoPostBack="true"
OnSelectedIndexChanged="DropDownList1_OnSelectedIndexChanged">
<asp:ListItem Text="First" Value="1" />
<asp:ListItem Text="Second" Value="2" />
<asp:ListItem Text="Third" Value="3" />
</asp:DropDownList>
<asp:HiddenField runat="server" ID="HiddenField1" />
</ItemTemplate>
</telerik:GridTemplateColumn>
protected void DropDownList1_OnSelectedIndexChanged(object sender, EventArgs e)
{
var gridDataItem = ((Control)sender).BindingContainer as Telerik.Web.UI.GridDataItem;
if (gridDataItem != null)
{
var hiddenField = gridDataItem.FindControl("HiddenField1") as HiddenField;
}
}