ASP.NET: How to set the css class of a Control during DataBind?

A table row is generated using an asp:Repeater: ``` <asp:repeater ID="announcementsRepeater" OnItemDataBound="announcementsRepeater_ItemDataBound" runat="Server"> <itemtemplate> <tr id="announcementRow" class="announcementItem" runat="server">...</tr> </itemtemplate> </asp:repeater> ``` Now in the data-bind i want to mark "unread" announcements with a different css class, so that the web-guy can perform whatever styling he wants to differentiate between read and unread announcements: ``` protected void announcementsRepeater_ItemDataBound(object sender, RepeaterItemEventArgs e) { if (e.Item.ItemType != ListItemType.Item && e.Item.ItemType != ListItemType.AlternatingItem) return; // get the associated data item Announcement announcement = (Announcement)e.Item.DataItem; WebControl row = (WebControl)e.Item.FindControl("announcementRow"); if (row != null) row.CssClass = row.CssClass + " announcementItemUnread"; } ``` except the cast fails at runtime: ``` System.InvalidCastException occurred Message="Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlTableRow' to type 'System.Web.UI.WebControls.WebControl'." ``` It turns out that `HtmlTableRow` has a different parent heirarchy than `WebControl`: ``` HtmlTableRow : HtmlContainerControl : HtmlControl : System.Web.UI.Control ``` which is ultimately where WebControl comes from ``` WebControl : System.Web.UI.Control ``` So i changed the code to try to use a System.Web.UI.Control instead: ``` Control row = (Control)e.Item.FindControl("announcementRow"); if (row != null) row.CssClass = row.CssClass + " announcementItemUnread"; ``` But `Control` doesn't contain a definition for `CssClass`: ``` 'System.Web.UI.Control' does not contain a definition for 'CssClass' ``` so how do i set the css class name for a `<TR>` element during DataBind?