关于DataGrid中<asp:ButtonColumn>列中按钮的事件触发问题。（发表很久了，一直没有得到解决！）

Question

<asp:DataGrid  id="ProductsDataGrid"
     AutoGenerateColumns="false"
     BorderWidth="2" BorderColor="lightgray" 
     CellPadding=2
     Font-Name="Verdana" Font-Size="8pt"
     Width="100%"
     BackColor="#ccccff"             
     ShowFooter="false"
     CellSpacing="0"            
     HeaderStyle-BackColor="#aaaadd"
     EnableViewState="false"
     AlternatingItemStyle-BackColor="lightskyblue"
     OnItemCommand="ProductsDataGrid_Cmd"     AllowPaging="true"  PageSize="10"
     OnPageIndexChanged="productNextPage"     DataKeyField="productid"
              
     AllowSorting="true"
     OnSortCommand="Sort_Grid"
     RunAt="server">    <Columns>     
     <asp:BoundColumn HeaderText="货品标识" DataField="productid" 
          ReadOnly="True" SortExpression="productid ASC"
          HeaderStyle-HorizontalAlign="center"
 ItemStyle-HorizontalAlign="center" ItemStyle-Wrap="false"/>
     <asp:BoundColumn HeaderText="货品名称" DataField="productname"
 SortExpression="productname ASC" 
          HeaderStyle-HorizontalAlign="center"
ItemStyle-HorizontalAlign="center"/>
     <asp:BoundColumn HeaderText="单位" DataField="unit"
          SortExpression="unit ASC" HeaderStyle-HorizontalAlign="center"
 ItemStyle-HorizontalAlign="center"/>
     <asp:BoundColumn HeaderText="安全库存" DataField="securitywarn"
 SortExpression="securitywarn ASC" 
          HeaderStyle-HorizontalAlign="center"
ItemStyle-HorizontalAlign="center"/>
     <asp:BoundColumn HeaderText="警告库存" DataField="securityerror"
 SortExpression="securityerror ASC" 
          HeaderStyle-HorizontalAlign="center"
 ItemStyle-HorizontalAlign="center"/>
     <asp:BoundColumn HeaderText="修改日期" DataField="updatedate" 
          ReadOnly="True" SortExpression="creatdate ASC" 
          HeaderStyle-HorizontalAlign="center"
          ItemStyle-HorizontalAlign="center" DataFormatString="{0:d}"/>
     <asp:ButtonColumn HeaderText="编辑" Text="编辑" 
          ButtonType="PushButton" CommandName="productedit"/>
     <asp:ButtonColumn HeaderText="删除" Text="删除"  
          ButtonType="PushButton" CommandName="productdelete"/>
   </Columns>
</asp:DataGrid>ProductsDataGrid_Cmd 中只需给屏幕上的变量赋个值，如“hello”.
现在的关键问题是没有办法触发ItemCommand事件。谢谢帮忙了！！