GridView1.DataSource = Enumerable.Range(0, 10);
        GridView1.DataBind();
        HyperLink link = GridView1.Rows[3].Cells[0].Controls[0] as HyperLink;
        link.NavigateUrl = null;

------解决方案--------------------
  <asp:TemplateField HeaderText="Header" SortExpression="Field">
           <ItemTemplate>
             <asp:HyperLink ID="HyperLink1" runat="server" navigateUrl='http://www.google.com' Text='Google'
                   Visible='<%# GetShowLink(Eval("flagShowLink"))%>'></asp:HyperLink>
           </ItemTemplate>
          </asp:TemplateField>
public bool  GetShowLink(object o)
{
//判断true,false