前台代码：
<asp:Label id="Message" runat="server"></asp:Label><BR>
            <asp:datagrid id="BigClassList" Width="100%" CellPadding="3" Runat="server" DataKeyField="BigClassID" OnUpdateCommand="MyDataGrid_Update" OnCancelCommand="MyDataGrid_Cancel" OnEditCommand="MyDataGrid_Edit" OnDeleteCommand="MyDataGrid_Del" OnSortCommand="MyDataGrid_Sort" OnItemCreated="MyDataGrid_ItemCreated" AutoGenerateColumns="False" AllowSorting="True">
                <HeaderStyle Font-Bold="True" BackColor="Gainsboro"></HeaderStyle>
                <Columns>
                    <asp:BoundColumn DataField="BigClassID" ReadOnly="True" HeaderText="大类编号" SortExpression="BigClassID"></asp:BoundColumn>
                    <asp:BoundColumn DataField="BigClassName" HeaderText="大类名称" SortExpression="BigClassName"></asp:BoundColumn>
                    <asp:BoundColumn DataField="BigClassSortID" HeaderText="排序编号" SortExpression="BigClassSortID"></asp:BoundColumn>
                    <asp:EditCommandColumn ButtonType="LinkButton" UpdateText="更新" CancelText="返回" EditText="编辑"></asp:EditCommandColumn>
                    <asp:TemplateColumn>
                        <ItemTemplate>
                            <asp:LinkButton id="cmdDel" runat="server" Text="删除" CommandName="Delete"></asp:LinkButton>
                        </ItemTemplate>
                    </asp:TemplateColumn>
                </Columns>
            </asp:datagrid>
            <table height="23" cellSpacing="0" cellPadding="3" width="100%" boder="0">
                <tr>
                    <td bgColor="#efefef">添加新大类</td>
                </tr>
          &nb