GridView如何根据某个列值来显示或不显示“删除”按钮

GridView怎么根据某个列值来显示或不显示“删除”按钮？
下面的GridView ，我想实现只有当“商品数”这一列（asp:HyperLinkField 列）为空时，才出现“删除”按钮，允许删除，不知应当怎么做？

    <asp:GridView ID="GridView1" runat="server" CellPadding="4" 

        AutoGenerateColumns="False"  CaptionAlign="Left" 

        Caption="优惠列表" onselectedindexchanged="GridView1_SelectedIndexChanged" 

        BackColor="White" BorderColor="#3366CC" BorderStyle="None" 

        BorderWidth="1px" onrowdatabound="GridView1_RowDataBound">

        <FooterStyle BackColor="#99CCCC" ForeColor="#003399" />

        <HeaderStyle BackColor="#003399" Font-Bold="True" ForeColor="#CCCCFF" />

        <PagerStyle BackColor="#99CCCC" ForeColor="#003399" HorizontalAlign="Left" />

        <RowStyle BackColor="White" ForeColor="#003399" />

        <SelectedRowStyle BackColor="#009999" Font-Bold="True" ForeColor="#CCFF99" />

    <Columns>

        <asp:BoundField DataField="SORT_ID" HeaderText="代码" Visible="false" />

        <asp:BoundField DataField="SORT_Name" HeaderText="优惠名称" />

        <asp:ImageField DataImageUrlField="Image1" 

            DataImageUrlFormatString="/UploadFiles/{0}">

<ControlStyle Height="72px"></ControlStyle>

        </asp:ImageField>

        <asp:HyperLinkField DataNavigateUrlFields="SORT_ID" DataTextField="C" DataNavigateUrlFormatString="ad_delhw.asp?sort_id={0}" HeaderText="商品数" />

        <asp:TemplateField>

            <ItemTemplate><a href='ad_new_promotion.asp?SID=<%# Eval("SORT_ID") %>'>添加优惠品</a></ItemTemplate>

        </asp:TemplateField>

       

        <asp:CommandField ShowSelectButton="True" />

       

        <asp:CommandField ShowDeleteButton="True" />

       

    </Columns>

    </asp:GridView>

------解决思路----------------------

 <asp:TemplateField>

                        <HeaderStyle BorderWidth="1" BorderColor="#c0c0c0" Font-Bold="false" Height="25px" BackColor="#efebde" />

                        <ItemStyle BorderWidth="1" BorderColor="#c0c0c0" Width="40" />

                        <HeaderTemplate>

                            删除

                        </HeaderTemplate>

                        <ItemTemplate>

                            <asp:Button ID="ButtonDelete" runat="server" Text="删除" Enabled='<%# Eval("qty") == DBNull.Value ? true : false %>'/>

                        </ItemTemplate>

                    </asp:TemplateField>