如何在C#的Picturebox上畫線畫圓

MSDN




public partial class Form1 : Form
    {
        Bitmap DrawArea;
        public Form1()
        {
            InitializeComponent();

            DrawArea = new Bitmap(pictureBox1.Size.Width, pictureBox1.Size.Height);
            pictureBox1.Image = DrawArea;
            
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Graphics g;
            g = Graphics.FromImage(DrawArea);
            
            Pen mypen = new Pen(Brushes.Black);
            g.DrawLine(mypen, 0, 0, 200, 200);
            g.Clear(Color.White);
            g.Dispose();
             
        }
        private void Button1_Click(object sender, EventArgs e)
        {
           
                Graphics g;
                g = Graphics.FromImage(DrawArea);
                
                Pen mypen = new Pen(Color.Black);

                g.DrawLine(mypen, 0,0,200,150);

                pictureBox1.Image = DrawArea;

                g.Dispose();
            
        }







private void pictureBox1_Paint(object sender, PaintEventArgs e)

        {

            int picBoxWidth = pictureBox1.Size.Width;

            int picBoxHeight = pictureBox1.Size.Height;

            int halfWidth = pictureBox1.Size.Width / 2;

            int halfHeight = pictureBox1.Size.Height / 2;

            Graphics objGraphic = e.Graphics; //**請注意這一行**

            Pen pen = new Pen(Color.Black);

            int b = 2; int m = 2; for (int x = 0; x < 426; x++)

            {

                int y = m * x + b; x = (y - b) / m;

                objGraphic.DrawLine(pen, x, y, -x, -y);

                System.Drawing.Drawing2D.GraphicsState graph = objGraphic.Save();

                objGraphic.Restore(graph);

            }

            objGraphic.DrawLine(pen, 0, halfHeight, picBoxWidth, halfHeight);

            objGraphic.DrawLine(pen, halfWidth, 0, halfWidth, picBoxHeight);

            objGraphic.DrawLine(pen, 20, 20, 300, 300);

        }










from:http://trufflepenne.blogspot.tw/2010/11/cpicturebox.html