protected void Repeater1_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
    {
        Repeater repeater2 = e.Item.FindControl("Repeater2") as Repeater;
        if (repeater2 != null)
        {
            repeater2.DataSource = 数据源;
            repeater2.DataBind();
        }
    }
}

页面代码：

<asp:Repeater ID="Repeater1" runat="server">
        <ItemTemplate>
            <asp:Repeater ID="Repeater2" runat="server" DataSource='<%#BackDataSourse(Eval("关联字段值").ToString())%>'>
                <ItemTemplate>                   
                     <%#Eval("遍历内容列")%>                       
                </ItemTemplate>
            </asp:Repeater>
        </ItemTemplate>
    </asp:Repeater>

后台代码：

1.先绑定Repeater1控件

2.返回绑定Repeater2r控件的数据源

 public DataTable BackDataSourse(string ColumnValue)
    {
        DataTable datasourse = new DataTable();

        //绑定数据表

        return datasourse;
    }

这不就OK了

if (!IsPostBack)
            {
              
                Repeater1.DataSource = categoryBLL.selectCategoryAll();
                Repeater1.DataBind();
                for (int i = 0; i < Repeater1.Items.Count; i++)
                {
                    Label la = (Label)Repeater1.Items[i].FindControl("Label1");
                    int ID = Convert.ToInt32(la.Text);
                    Repeater re = (Repeater)Repeater1.Items[i].FindControl("Repeater2");
                    re.DataSource = seriesBLL.selectSeriesAll(ID);
                    re.DataBind();
                }
            }

在对应页面中的pageload事件中写