保存绘制图像的图片框

Question

我的程序允许用户在图片框中绘制。我正在尝试将pictureBox1保存为.jpg文件，但此文件为空。我的保存按钮：

Bitmap bm = new Bitmap(pictureBox1.ClientSize.Width, pictureBox1.ClientSize.Height);
this.pictureBox1.DrawToBitmap(bm, this.pictureBox1.ClientRectangle);
bm.Save(String.Format("{0}.jpg", this.ID));
this.pictureBox1.CreateGraphics().Clear(Color.White);

我的抽奖活动：

private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        drawNote.isDraw = true;
        drawNote.X = e.X;
        drawNote.Y = e.Y;
    }

private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
    {
        if(drawNote.isDraw)
        {
            Graphics G = pictureBox1.CreateGraphics();
            G.DrawLine(drawNote.pen, drawNote.X, drawNote.Y, e.X, e.Y);

            drawNote.X = e.X;
            drawNote.Y = e.Y;

        }
    }

谢谢！

Answer 1

您应该将graphics存储在全局变量中并用于保存。

Graphics graphics = null;
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
    if(drawNote.isDraw)
    {
        if (graphics == null) 
        {
            Bitmap bm = new Bitmap(pictureBox1.ClientSize.Width, pictureBox1.ClientSize.Height);
            pictureBox1.Image = bm;
            graphics = pictureBox1.CreateGraphics();
        }

        graphics.DrawLine(drawNote.pen, drawNote.X, drawNote.Y, e.X, e.Y);

        graphics.Save();

        drawNote.X = e.X;
        drawNote.Y = e.Y;
    }
}

您可以通过以下简单代码来完成此操作：

using (FileStream fileStream = new FileStream(@"C:\test.jpg", FileMode.Create))
{
    pictureBox1.Save(fileStream, orginalImage.RawFormat);
}