pictureBox绘图保存问题

Question

现在程序可以在pictureBox上随意绘图,但保存的时候picturebox.image里为什么是null??

Answer 1

最后将画完的image保存进picturebox.image。这步不是自动实现的，需要写代码

Answer 2

具体怎么写,我现在用的鼠标事件绘的图,但保存时候pictureBox1里空的
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {
            this.CanMove = true;
            startpt.X = e.X;
            startpt.Y = e.Y;
        }        private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
            if (this.CanMove == true)
            {
                Graphics g = pictureBox1.CreateGraphics();
                endpt.X = e.X;
                endpt.Y = e.Y;
                g.DrawLine(new Pen(Color.Red, 1), startpt, endpt);
                startpt = endpt;
            }
        }        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
        {
            Graphics g = this.CreateGraphics();
            g.DrawLine(new Pen(Color.Red, 1), this.startpt, new Point(e.X, e.Y));
            this.CanMove = false;
        }