In my own dealings, I've had to take control of how a DataGrid was rendered. One particular example is adding a Totals row to a grid BEFORE the footer. Here's a sample:

<asp:DataGrid ID="dgd" Runat="server" AutoGenerateColumns="False">

   <Columns>

      <asp:BoundColumn DataField="Product" HeaderText="Product"/>

      <asp:BoundColumn DataField="Price" HeaderText="Price" DataFormatString="{0:C}"/>

      <asp:EditCommandColumn EditText="Edit" UpdateText="Update" CancelText="Cancel" />

   </Columns>

</asp:DataGrid>

And the code:

        private void Page_Load(object sender, System.EventArgs e)

        {

            //creating mock table for data

            DataTable dt = new DataTable();

            dt.Columns.Add("Product");

            dt.Columns.Add("Price");

            dt.Rows.Add(new object[]{"Shoes", "12.90"});

            dt.Rows.Add(new object[]{"Socks", "3.50"});

            dt.Rows.Add(new object[]{"Underpants", "8.40"});

            //binding mock data

            dgd.DataSource = dt;

            dgd.DataBind();

            

            //adding totals row

            DataGridItem row = new DataGridItem(-1, -1, ListItemType.Separator);

            TableCell cell = new TableCell();

            row.Cells.Add(cell);

            cell = new TableCell();

            //calculate total

            decimal total = 0;

            foreach(DataGridItem dgi in dgd.Items)

            {

                total += decimal.Parse(dgi.Cells[1].Text);

            }

            cell.Font.Bold = true;

            cell.Text = total.ToString("c");

            row.Cells.Add(cell);

            cell = new TableCell();

            row.Cells.Add(cell);

            dgd.Controls[0].Controls.Add(row);

        }
I merely create a new DataGridItem, add what I want, and add it to my grid. I've used this concept several times, and I hope it helps out someone else.