Sorry if I couldn't explain my problem very clearly. Let me try one more time.  

If we wrote the code like that,  

HTML View 

        <asp:GridView ID="GridView1" runat="server" >           
        </asp:GridView>

Code-behinded File 

protected void Page_Load(object sender, EventArgs e)
    {
        List<string> list = new List<string>();
        list.Add("Alien");

        GridView1.DataSource = list;
        GridView1.DataBind();  

    }
    

the HTML tag will be generated as fellows by default ~

 <table cellspacing="0" rules="all" border="1" id="GridView1" style="border-collapse:collapse;">
            <tr>
                <td>Alien</td>
            </tr><tr>             
 </table>

I noticed that there is no thead or tbody or tfoot in the generated HTML table. I want GridView to generate the HTML table with those tags. So, I tried with the follwing code.

        //This replaces <td> with <th> and adds the scope attribute
         grid.UseAccessibleHeader = true;

        //This will add the <thead> and <tbody> elements
        grid.HeaderRow.TableSection = TableRowSection.TableHeader;
        grid.HeaderRow.CssClass = "fixedHeader";
           
        //This adds the <tfoot> element. Remove if you don't have a footer row
        grid.FooterRow.TableSection = TableRowSection.TableFooter;

 then, I can add thead, tbody and tfoot to generated HTML successfully.  It allows me to set the custom CSS class by using HeaderRow.CssClass and FooterRow.CssClass properties. But I found no way to specify the custom CSS class for tbody. So, it would be great if anyone tell me to achieve this goal.

Thanks in advance.