gridview

我想用vs2005（vb）中的gridview中的编辑列中的可用字段中的commandfiled中的编辑、更新、取消功能
代码如下：（代码段的最后一句话updatecommand该如何写？）
   <asp:GridView ID="GridView2" runat="server" AllowPaging="True" AllowSorting="True"
            AutoGenerateColumns="False" CellPadding="4" DataSourceID="AccessDataSource2"
            ForeColor="#333333" GridLines="None">
            <FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
            <Columns>
                <asp:BoundField DataField="原主题编号" HeaderText="原主题编号" SortExpression="原主题编号" />
                <asp:ImageField DataAlternateTextField="图标" DataAlternateTextFormatString="http://{0}"
                    DataImageUrlField="图标" HeaderText="图标">
                </asp:ImageField>
                <asp:TemplateField HeaderText="作者" SortExpression="作者">
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("作者") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:HyperLink ID="HyperLink2" runat="server" NavigateUrl='<%# Eval("邮件帐号", "mailto:{0}") %>'
                            Text='<%# Eval("作者") %>'></asp:HyperLink>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="主题" HeaderText="主题" SortExpression="主题" />
                <asp:BoundField DataField="内容" HeaderText="内容" SortExpression="内容" />
                <asp:BoundField DataField="时间" HeaderText="时间" SortExpression="时间" />
                <asp:CommandField HeaderText="功能" ShowEditButton="True" />
            </Columns>
            <RowStyle BackColor="#E3EAEB" />
            <EditRowStyle BackColor="#7C6F57" />
            <SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" />
            <PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />
            <HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />
            <AlternatingRowStyle BackColor="White" />
        </asp:GridView>
        <asp:AccessDataSource ID="AccessDataSource2" runat="server" DataFile="~/ly/Data.mdb"
            SelectCommand="SELECT * FROM [回复区] ORDER BY [时间] DESC"
            updatecommand="update [回复区] set [主题] , [作者]"></asp:AccessDataSource>