datalist嵌套中子datalist数据绑定的处理

protected void dlArea1_ItemDataBound(object sender, DataListItemEventArgs e)
{
int index = e.Item.ItemIndex;
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
DataList dl = (DataList)e.Item.FindControl("dlArea2");
int parentid = Convert.ToInt32(this.dlArea1.DataKeys[index].ToString());
DataTable subTable = country.getAreaList(parentid);
dl.DataSource = subTable;
dl.DataBind();
}
}

<asp:DataList ID="dlArea1" runat="server" DataKeyField="areaid" Width="500px" OnCancelCommand="dlArea1_CancelCommand" OnEditCommand="dlArea1_EditCommand" OnUpdateCommand="dlArea1_UpdateCommand" OnItemDataBound="dlArea1_ItemDataBound" OnDeleteCommand="dlArea1_DeleteCommand">
<ItemTemplate>
<asp:LinkButton ID="lbtEdit" runat="server" Width="40px" CommandName="Edit">编辑</asp:LinkButton>
<asp:LinkButton ID="lbtDel" runat="server" Width="40px" CommandName="Delete" OnClientClick="javascript:return confirm('你确定要删除这个代理地区吗？');">删除</asp:LinkButton>
<asp:Label ID="lblCountryName" runat="server" Text='<%#Eval("cname") %>' CssClass="nameblue"></asp:Label> <asp:Label ID="lblArea1Name" runat="server" Text='<%# Eval("areaname") %>' Width="150px"></asp:Label>
</ItemTemplate>
<SeparatorTemplate>
<div class="split1">
</div>
</SeparatorTemplate>
<ItemStyle Font-Bold="True" HorizontalAlign="Left" />
<EditItemTemplate>
<asp:LinkButton ID="lbtUpdate" runat="server" CommandName="Update" Width="40px">更新</asp:LinkButton>
<asp:LinkButton ID="lbtCancel" runat="server" CommandName="Cancel" Width="40px">取消</asp:LinkButton>
<asp:DropDownList ID="ddlCountry" runat="server">
</asp:DropDownList>
<asp:HiddenField ID="hfCountryName" runat="server" Value='<%#Eval("cname") %>' />
<asp:TextBox ID="tbAddr1" runat="server" Text='<%#Eval("areaname") %>' Width="100px"></asp:TextBox>
</EditItemTemplate>
</asp:DataList>