Visual Basic - Add line(s) on individual rows in datagridview - Flickering

I have a datagridview in my application (at this moment Visual Basic 2008, but in the near future Visual Basic 2010) and I want to create line(s) in individual rows.

At this moment I use the following code:

Private Sub datagridview1_CellPainting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellPaintingEventArgs) Handles datagridview1.CellPainting

        Dim row As DataGridViewRow = datagridview1.Rows(e.RowIndex)
               
        Dim BackColorBrush As New SolidBrush(e.CellStyle.BackColor)
       	Dim GridBrush As New SolidBrush(Me.datagridview1.GridColor)
        Dim GridLinePen As New Pen(GridBrush)

      	' -- Erase the cell
       	e.Graphics.FillRectangle(BackColorBrush, e.CellBounds)
                     
      	Dim ProgressBarBrush As New SolidBrush(Color.Black)
      	Dim CellProgressBarRect As New Rectangle(e.CellBounds.X, e.CellBounds.Y, e.CellBounds.Width, 2)
       	e.Graphics.FillRectangle(ProgressBarBrush, CellProgressBarRect)

     	e.Handled = True
                        
      	Dim style As New DataGridViewCellStyle
      	style.Font = New Font(datagridview1.Font, FontStyle.Bold)
      	datagridview1.Rows(e.RowIndex).DefaultCellStyle = style

End Sub

It works fine, but I have one problem:

The line(s) are 'flickering' on my screen. I know it happened by the CellPainting, but I don't know how to fix that. Does anyone know how to fix that?