Merge rows in a datagrid

datagrid doesnt support Merging

in order to perform what you want you will need todo it on the DataTable level

here is the howto from MS home:

http://support.microsoft.com/kb/326080

enjoy

try this code,

protected void grdEmployee_ItemDataBound(object sender, DataGridItemEventArgs e)
{
    if (chkChangetoNormal.Checked)
       {
       // Apply Row span for all even rows

         if (e.Item.ItemIndex % 2 == 0 )
       {
        e.Item.Cells[0].RowSpan = 2;
        e.Item.Cells[1].RowSpan = 2;
       }
       // Remove the extra cells created due to row span for odd rows

       if (e.Item.ItemIndex % 2 == 1 )
       {
        e.Item.Cells.RemoveAt(0); 
        e.Item.Cells.RemoveAt(0); 
        e.Item.Cells[1].HorizontalAlign = HorizontalAlign.Center ;
       }
    }
}

show this article also 
more info