picturebox画图， 已经实现，求如何保存图片

Question

那你就在按钮里重新执行
Graphics g = pictureBox1.CreateGraphics();
并把它画到一个新建Image里,然后save

Answer 1

Graphics g = pictureBox1.CreateGraphics();
//Graphics g = Graphics.FromImage(this.pictureBox1.Image);被你注释掉的那句不就可以么，不要创建 Graphics
另外 Graphics 的 Dispose 不要忘了

Answer 2

不要在MouseMove里面CreateGraphics，它会导致GDI资源泄露，一定时间后可能会导致程序崩溃等。
用this.pictureBox1.Invalidate来强迫它更新。
用数据结构（那些currentScribble ，scribbles）等来保存自定义标志，并在更新，或存图的时候重画。
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        this.pictureBox1.Paint += pictureBox1_Paint;  // 可以移动到设计器生成代码里
    }    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        currentScribble = new List<Point>();
        currentScribble.Add(e.Location);
    }    private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left && this.currentScribble != null)
        {
            currentScribble.Add(e.Location);
            RedrawPictureBox();
        }
    }    List<Point> currentScribble = null;
    List<Point[]> scribbles = new List<Point[]>();
    void pictureBox1_Paint(object sender, PaintEventArgs e)
    {
        using (Pen pen = new Pen(Color.Blue, 2))
        {
            foreach (Point[] points in scribbles)
            {
                e.Graphics.DrawLines(pen, points);
            }
            if (this.currentScribble != null)
            {
                e.Graphics.DrawLines(pen, this.currentScribble.ToArray());
            }
        }
    }    private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
    {
        if (currentScribble != null && currentScribble.Count > 1)
        {
            RedrawPictureBox();
            this.scribbles.Add(currentScribble.ToArray());
        }
        this.currentScribble = null;
    }    private void RedrawPictureBox()
    {
        if (currentScribble.Count >= 2)
        {
            Rectangle last = new Rectangle(currentScribble[currentScribble.Count - 2], Size.Empty);
            Rectangle current = new Rectangle(currentScribble[currentScribble.Count - 1], Size.Empty);
            Rectangle invalidateArea = Rectangle.Inflate(Rectangle.Union(last, current), 2, 2);
            this.pictureBox1.Invalidate(invalidateArea);
        }
    }    private void button5_Click(object sender, EventArgs e)
    {
        Rectangle rect = new Rectangle(Point.Empty, this.pictureBox1.Size);
        using (Bitmap bmp = new Bitmap(rect.Width, rect.Height))
        {
            this.pictureBox1.DrawToBitmap(bmp, rect);  // 画pictureBox1显示的图，假定它没有边框
            using (Graphics g = Graphics.FromImage(bmp))
            {
                pictureBox1_Paint(this, new PaintEventArgs(g, rect)); // 画自定义标记
            }
            bmp.Save(@"D:\2.jpg", ImageFormat.Jpeg);
        }
        MessageBox.Show("ok");
    }
}