求助：如何实现Asp.net的GridView里Linkbutton的enable=false？？？

我在Asp.net前台页面Source里面添加了一个GridView，里面嵌套了一个Linkbutton.前台代码如下：

 <asp:GridView ID="GridView2" runat="server" AllowPaging="True" OnPageIndexChanging="gvOrderList2_PageIndexChanging" EnableModelValidation="false" Height="308px" Style="margin-top: 0px" Width="544px" DataKeyNames="OrderID"  AutoGenerateColumns="False" AllowSorting="True" PageSize="12" BackColor="#FFCC99" BorderColor="#FFCC00" OnRowDataBound="GridView2_RowDataBound" OnDataBound="GridView2_OnDataBound">
<Columns>
<asp:BoundField HeaderText="序号" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField>  
<asp:BoundField DataField="OrderID" HeaderText="订单号" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField> 
<asp:BoundField DataField="OrderDate" HeaderText="订单日期" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField>                                                                
<asp:BoundField DataField="GoodsName" HeaderText="商品名称" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField>  
<asp:BoundField DataField="HotPrice" HeaderText="单价(￥)" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField> 
<asp:BoundField DataField="Num" HeaderText="数量" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField>  
<asp:BoundField DataField="ShipFee" HeaderText="运费(￥)" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField>  
<asp:BoundField DataField="TotalPrice" HeaderText="总价(￥)" ReadOnly="True">
<ItemStyle HorizontalAlign="Center" />
<HeaderStyle HorizontalAlign="Center" />
</asp:BoundField>  
<asp:TemplateField>
<HeaderStyle HorizontalAlign=Center />
<ItemStyle HorizontalAlign =Center />
<ItemTemplate >
<asp:LinkButton ID="lnkbtnGoPay" runat="server" OnClick="lnkbtnGoPay_OnClick" CommandArgument='<%#Eval("OrderID") %>' OnCommand="lnkbtnGoPay_Command">去付款</asp:LinkButton>
</ItemTemplate>    
</asp:TemplateField>
</Columns>
</asp:GridView>

运行效果如下图（这幅图是订单类型为“未付款”时效果）：

问题：在后台代码中：
当订单类型为“已付款”时，我如何实现将GridView最后一列的“去付款”属性Enable=false？？？
恳请各位行家高手不吝惜指教！万分感谢！！