ASP.NET:如何在 DataBind 期间设置控件的 css 类？

Question

使用 asp:Repeater 生成表格行:

<asp:repeater ID="announcementsRepeater" OnItemDataBound="announcementsRepeater_ItemDataBound" runat="Server">
   <itemtemplate>
      <tr id="announcementRow" class="announcementItem" runat="server">...</tr>
   </itemtemplate>
</asp:repeater>

现在在数据绑定(bind)中，我想用不同的 css 类标记“未读”公告，以便网络专家可以执行他想要区分已读和未读公告的任何样式:

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";
}

除了运行时转换失败:

System.InvalidCastException occurred
  Message="Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlTableRow' to type 'System.Web.UI.WebControls.WebControl'."

事实证明HtmlTableRow具有与 WebControl 不同的父层次结构:

HtmlTableRow
   : HtmlContainerControl
      : HtmlControl
         : System.Web.UI.Control

WebControl 的最终来源

WebControl
   : System.Web.UI.Control

所以我更改了代码以尝试改用 System.Web.UI.Control:

Control row = (Control)e.Item.FindControl("announcementRow");
if (row != null)
   row.CssClass = row.CssClass + " announcementItemUnread";

但是Control不包含 CssClass 的定义:

'System.Web.UI.Control' does not contain a definition for 'CssClass'    

那么我如何为 <TR> 设置 css 类名呢？ DataBind 期间的元素？

Answer 1

   HtmlControl htmlRow = (HtmlControl)row; 
   htmlRow.Attributes["class"] = htmlRow.Attributes["class"] + " announcementItemUnread";