親代窗口，放這個picturebox的Control，通常為form或panel

不過我程式寫錯了，你改一下

pb.Parent = this ;
或
this.Controls.Add(pb);

我最開頭的程式修改一下，不用放panel，把form的屬性doublebuffer 設成enable

程式改成以下，Timer.interval 改成 30 (33 FPS)都不會閃爍了！

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace pinBall
{
    public partial class Form1 : Form
    {
        List<ball> balls = new List<ball>();
        public Form1()
        {
            InitializeComponent();
        }

        private void drawballs(Graphics g)
        {
            foreach (var b in balls)
            {
                using (Brush sb = new SolidBrush(b.color))
                {
                    g.FillEllipse(sb, b.pos.X - b.r, b.pos.Y - b.r, b.R, b.R);
                }
                b.move(); // 下一步
            }
        }


        private void Form1_Load(object sender, EventArgs e)
        {
            for (int b = 1; b <= 10; b++) // 產生10個球並存入 List of ball裡
            {
                balls.Add(new ball(Width, Height, 50));
            }
            timer1.Interval = 30;
            timer1.Enabled = true;
        }

        private void panel1_Paint(object sender, PaintEventArgs e)
        {
            
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            this.Invalidate();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            drawballs(e.Graphics);
        }
    }
    class ball
    {
        public Color color { get; set; }
        public PointF pos { get; set; }
        public int directionX { get; set; }
        public int directionY { get; set; }
        public int R { get; set; }
        public float r { get; set; } //半徑
        private int pWidth { get; set; }
        private int pHeight { get; set; }
        public ball(int width, int height, int ballR)
        {
            Random rnd = new Random(Guid.NewGuid().GetHashCode());
            pos = new PointF(rnd.Next(ballR, width - ballR), rnd.Next(ballR, height - ballR));
            directionX = 5 - rnd.Next(10);
            directionY = 5 - rnd.Next(10);
            R = ballR; // 直徑 
            r = R / 2;
            pWidth = width;
            pHeight = height;
            color = Color.FromArgb(255, rnd.Next(255), rnd.Next(255), rnd.Next(255));
        }
        public void move()
        {
            if (pos.X + directionX + R >= pWidth)
            {
                directionX *= -1;
            }
            if ((pos.X + directionX) - R <= 0)
            {
                directionX = Math.Abs(directionX);
            }
            if (pos.Y + directionY + R >= pHeight)
            {
                directionY *= -1;
            }
            if ((pos.Y + directionY) - R <= 0)
            {
                directionY = Math.Abs(directionY);
            }
            pos = new PointF(pos.X + directionX, pos.Y + directionY);
        }
    }
}

謝謝您~

是這個意思嗎?
https://social.msdn.microsoft.com/Forums/zh-TW/acd26f78-0ba8-4987-879f-5872bba71770/3553121839-38364picturebox-2356525033-3849921015-303402183938988?forum=233

迴圈的部分我不是很清楚本人沒碰過幾次..可以加以解說指點嗎謝謝不好意思

類似這樣吧...

List<PictureBox> pictureList;
function 建構式()
{
   pictureList = new List<PictureBox>();
}

function xxx()
{
    for(int i=0;i<?;i++)
    {
       PictureBox picture = new PictureBox();
       picture.Left = xxx;
       picture.Top = xxx;
       ...
       ...
       plctureList.add(picture);
    }
}

之類的,
不過要把picturebox加到control中.