关于pictureBox1.Image的问题

Question

首先在pictureBox上画了个图，但如何引用这个图？
即把我画的这个图变成pictureBox的Image属性，因为我想接着对它进行放大，但放大时需要用到pictureBox1.Image！望高手指教！！谢谢

Answer 1

怎么画的？用GDI+?
Graphics g = pictureBox.CreateGraphics();

Answer 2

是这样的：
System.Drawing.Graphics  mydraw;
mydraw=pictureBox1.CreateGraphics();
mydraw.DrawLine(......)
绘出了一个分形图

Answer 3

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;namespace 实验程序
{
    
    public partial class Form1 : Form
    {
        Image pbImg = null;
        Rectangle rect = new Rectangle(50, 50, 100, 100);
        public Form1()
        {
            InitializeComponent();
            pbImg = new Bitmap(pictureBox1.Width, pictureBox1.Height);
            DrawSomething(Graphics.FromImage(pbImg), rect);
            pictureBox1.Image = pbImg;
        }        private void DrawSomething(Graphics g,Rectangle rec)
        {
            g.Clear(pictureBox1.BackColor);
            g.DrawRectangle(new Pen(Color.Red, 1), rec);
        }        private void btn_ZoomIn_Click(object sender, EventArgs e)
        {
            int x = rect.Left * 2 + (1 - 2) * pictureBox1.Width / 2;
            int y = rect.Top * 2 + (1 - 2) * pictureBox1.Height / 2;
            int w = rect.Width * 2;
            int h = rect.Height * 2;
            rect = new Rectangle(x, y, w, h);
            DrawSomething(Graphics.FromImage(pbImg), rect);
            pictureBox1.Image = pbImg;
        }        private void btn_ZoomOut_Click(object sender, EventArgs e)
        {
            int x = (int)(rect.Left * 0.5 + (1 - 0.5) * pictureBox1.Width / 2);
            int y = (int)(rect.Top * 0.5 + (1 - 0.5) * pictureBox1.Height / 2);
            int w = (int)(rect.Width * 0.5);
            int h = (int)(rect.Height * 0.5);
            rect = new Rectangle(x, y, w, h);
            DrawSomething(Graphics.FromImage(pbImg), rect);
            pictureBox1.Image = pbImg;
        }
    }}