After Scrolling vertically datagridview repaints and flicker

protected override CreateParams CreateParams
    {
        get
        {
            CreateParams cp = base.CreateParams;
            cp.ExStyle |= 0x02000000;   // WS_EX_COMPOSITED
            return cp;
        }
    } 
//and add below code in form constructor after ' InitializeComponent(); ' method
// Enable double duffering to stop flickering.
        this.SetStyle(ControlStyles.DoubleBuffer, true);
        this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
        this.SetStyle(ControlStyles.UserPaint, true);
        this.SetStyle(ControlStyles.SupportsTransparentBackColor, false);
        this.SetStyle(ControlStyles.Opaque, false);
        this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
        this.SetStyle(ControlStyles.ResizeRedraw, true);

void dgvprdgrp_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {

            if (e.RowIndex == -1 && e.ColumnIndex > -1)
            {

                e.PaintBackground(e.CellBounds, false);

                Rectangle r2 = e.CellBounds;

                r2.Y += e.CellBounds.Height / 2;

                r2.Height = e.CellBounds.Height / 2;

                e.PaintContent(r2);

                e.Handled = true;

            }

        }