又是一个用户控件“未实例引用问题”～！

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="Category.ascx.cs" Inherits="Common_Category" %>
        <asp:Repeater ID="rpt_BCategory" runat="server" DataSourceID="obds_BCategory" OnItemDataBound="rpt_BCategory_ItemDataBound">
        <HeaderTemplate>
          <table width="180" border="0" cellspacing="1" cellpadding="2">
        </HeaderTemplate>
        <ItemTemplate>
          <tr valign="middle"><td width="16"><img src="pic/arrow.gif" border="0" /></td><td class="titlefont"><b><%# Eval("Name") %></b>
              <asp:HiddenField ID="h_BCID" runat="server" Value='<%# Eval("BCID") %>' />
          </td></tr>
          <tr><td colspan="2">
        
          <asp:DataList ID="dlsc" runat="server" Width="180" RepeatColumns="3" RepeatDirection="Horizontal" RepeatLayout="Table" ShowFooter="False" ShowHeader="False">
          <ItemStyle  Width="60"/>
          <ItemTemplate><a  href="Index.aspx?SCID=<%# Eval("SCID") %>" ><%# Eval("Name") %></a></ItemTemplate>
          </asp:DataList><br />
                                
          </td></tr>
        </ItemTemplate>
        <FooterTemplate>
          </table>
        </FooterTemplate>
        </asp:Repeater>
        <asp:ObjectDataSource ID="obds_BCategory" runat="server" SelectMethod="getBCategoryAll" TypeName="WZTBLL.BCategory"></asp:ObjectDataSource>
cs:
protected void rpt_BCategory_ItemDataBound(object sender, RepeaterItemEventArgs e)
    {
        DataList dlsc = (DataList)e.Item.FindControl("dlsc");
        HiddenField h_BCID = (HiddenField)e.Item.FindControl("h_BCID");
        int BCID = int.Parse(h_BCID.Value);------------------------------------
        dlsc.DataSource = SCategory.getSCategoryAllByBCID(BCID);---------------error
        dlsc.DataBind();-------------------------------------------------------
    }