將以下function 在資料放入gridview後再呼叫即可，記得將gridview名稱換掉喔!

Public Sub datagriviewheader_idx()
    For count = 0 To DataGridView1.Rows.Count - 1
        DataGridView1.Rows(count).HeaderCell.Value = String.Format("{0}", count + 1)
    Next
End Sub