Diaplay image issue

I have a picture box (picture box 1) and in that box have drawn a rectangle and displayed the drawn portion using another picture box (picture box 2). Problem is when i draw rectangle (in picture box 1)the picture box 2 will not shows up but when change the position of the form (move the form) the picture box 2 shows up.

How to display the drawn potion...

private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
    using (Pen pen = new Pen(Color.Green, 2))
    {
        pen.Color = Color.Red;
        pen.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;

        e.Graphics.D开发者_运维百科rawRectangle(pen, rect);

        foreach (Rectangle r in rectangles)
        {
            label1.Top = r.Top; label1.Left = r.Left; label1.Width = r.Width;
            label1.Height = r.Height;
            e.Graphics.DrawRectangle(pen, r);
            e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), r);
        }
    }

    if (!(rect.Width <= 0 | rect.Height <= 0))
    {
        sz1.Width = rect.Width * Convert.ToInt16(1.5);
        sz1.Height = rect.Height * Convert.ToInt16(1.5);
        pictureBox2.Size = sz1;
        w.X = 500; w.Y = 20;
        pictureBox2.Location = w;
        Bitmap niv = new Bitmap(pictureBox2.Width, pictureBox2.Height);
        using (Graphics g1 = Graphics.FromImage(niv))
        {
            g1.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g1.DrawImage(pictureBox1.Image, pictureBox2.ClientRectangle, rect, GraphicsUnit.Pixel);
        }

        pictureBox2.Image = niv;
        pictureBox2.Visible = true;
        pictureBox2.Invalidate();
    } 
}

You can paint or repainting your picturebox using the OnPaint event.

I got it. just right click on the picture box2 and selected "Bring to Front" option.