winfrom中将panel另存为图片

private void button1_Click(object sender, EventArgs e)
        {
            Point ScrollMaxInfo = GetScrollPoint(panel1);
            Size ControlMaxSize = GetControlSize(panel1, ScrollMaxInfo);

            Bitmap ControlImage = new Bitmap(ControlMaxSize.Width, ControlMaxSize.Height);
            Graphics MainGraphics = Graphics.FromImage(ControlImage);
            Bitmap TempImage = new Bitmap(panel1.Width - 16, panel1.Height - 16);

            int StepWidth = GetScrollNumb(panel1.Width - 16, ScrollMaxInfo.X);
            int StepHeight = GetScrollNumb(panel1.Height - 16, ScrollMaxInfo.Y);

            int LogWidth = 0;
            int LogHeigh = 0;
            MoveBar(0, 0, panel1);

            for (int i = 0; i != StepWidth; i++)
            {
                MoveBar(1, 0, panel1);
                LogHeigh = 0;
                for (int z = 0; z != StepHeight; z++)
                {
                    panel1.DrawToBitmap(TempImage, new Rectangle(0, 0, panel1.Width - 16, panel1.Height - 16));
                    MainGraphics.DrawImage(TempImage, LogWidth, LogHeigh);
                    MoveBar(1, panel1.Height - 16 + LogHeigh, panel1);
                    LogHeigh = GetScrollPoint(1, panel1);
                }
                MoveBar(0, panel1.Width - 16 + LogWidth, panel1);
                LogWidth = GetScrollPoint(0, panel1);
            }
            MainGraphics.Dispose();
            TempImage.Dispose();
            ControlImage.Save(System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase + "123.png");
        }

        #region API
        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
        public struct SCROLLINFO
        {
            public uint cbSize;
            public uint fMask;
            public int nMin;
            public int nMax;
            public uint nPage;
            public int nPos;
            public int nTrackPos;
        }
        public enum ScrollBarInfoFlags
        {
            SIF_RANGE = 0x0001,
            SIF_PAGE = 0x0002,
            SIF_POS = 0x0004,
            SIF_DISABLENOSCROLL = 0x0008,
            SIF_TRACKPOS = 0x0010,
            SIF_ALL = (SIF_RANGE | SIF_PAGE | SIF_POS | SIF_TRACKPOS)
        }
        public enum ScrollBarRequests
        {
            SB_LINEUP = 0,
            SB_LINELEFT = 0,
            SB_LINEDOWN = 1,
            SB_LINERIGHT = 1,
            SB_PAGEUP = 2,
            SB_PAGELEFT = 2,
            SB_PAGEDOWN = 3,
            SB_PAGERIGHT = 3,
            SB_THUMBPOSITION = 4,
            SB_THUMBTRACK = 5,
            SB_TOP = 6,
            SB_LEFT = 6,
            SB_BOTTOM = 7,
            SB_RIGHT = 7,
            SB_ENDSCROLL = 8
        }
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern int GetScrollInfo(IntPtr hwnd, int bar, ref SCROLLINFO si);
        [DllImport("user32")]
        public static extern int SetScrollPos(IntPtr hWnd, int nBar, int nPos, bool Rush);
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern int SendMessage(IntPtr hWnd, int msg, int wParam, int lParam);
        #endregion

        /// <summary>
        /// 获取目前滚动条位置
        /// </summary>
        /// <param name="Bar"></param>
        /// <param name="MyControl"></param>
        /// <returns></returns>
        public static int GetScrollPoint(int Bar, Control MyControl)
        {
            SCROLLINFO ScrollInfo = new SCROLLINFO();
            ScrollInfo.cbSize = (uint)System.Runtime.InteropServices.Marshal.SizeOf(ScrollInfo);
            ScrollInfo.fMask = (uint)ScrollBarInfoFlags.SIF_ALL;

            GetScrollInfo(MyControl.Handle, Bar, ref ScrollInfo);

            return ScrollInfo.nPos;
        }
        /// <summary>
        /// 获取循环几次获得图形
        /// </summary>
        /// <returns></returns>
        private static int GetScrollNumb(int MyControlNumb, int ScrollMaxInfoNumb)
        {
            double Step = (double)ScrollMaxInfoNumb / (double)MyControlNumb;
            Step++;

            if ((int)Step == Step)
            {
                return (int)Step;
            }
            else
            {
                return (int)Step + 1;
            }
        }
        /// <summary>
        /// 获得控件不需要滚动条的宽和高（最终图形大小）
        /// </summary>
        /// <param name="MyControl"></param>
        /// <param name="ScrollMaxInfo"></param>
        /// <returns></returns>
        private static Size GetControlSize(Control MyControl, Point ScrollMaxInfo)
        {
            return new Size(MyControl.Size.Width + ScrollMaxInfo.X - 16, MyControl.Size.Height + ScrollMaxInfo.Y - 16);
        }
        /// <summary>
        /// 获取滚动条数据
        /// </summary>
        /// <param name="MyControl"></param>
        /// <param name="ScrollSize"></param>
        /// <returns></returns>
        private static Point GetScrollPoint(Control MyControl)
        {
            Point MaxScroll = new Point();

            SCROLLINFO ScrollInfo = new SCROLLINFO();
            ScrollInfo.cbSize = (uint)System.Runtime.InteropServices.Marshal.SizeOf(ScrollInfo);
            ScrollInfo.fMask = (uint)ScrollBarInfoFlags.SIF_ALL;

            GetScrollInfo(MyControl.Handle, 1, ref ScrollInfo);
            MaxScroll.Y = ScrollInfo.nMax - (int)ScrollInfo.nPage;
            if ((int)ScrollInfo.nPage == 0) MaxScroll.Y = 0;
            GetScrollInfo(MyControl.Handle, 0, ref ScrollInfo);
            MaxScroll.X = ScrollInfo.nMax - (int)ScrollInfo.nPage;
            if ((int)ScrollInfo.nPage == 0) MaxScroll.X = 0;
            return MaxScroll;
        }
        /// <summary>
        /// 移动控件滚动条位置
        /// </summary>
        /// <param name="Bar"></param>
        /// <param name="Point"></param>
        /// <param name="MyControl"></param>
        private static void MoveBar(int Bar, int Point, Control MyControl)
        {
            if (Bar == 0)
            {
                SetScrollPos(MyControl.Handle, 0, Point, true);
                SendMessage(MyControl.Handle, (int)0x0114, (int)ScrollBarRequests.SB_THUMBPOSITION, 0);
            }
            else
            {
                SetScrollPos(MyControl.Handle, 1, Point, true);
                SendMessage(MyControl.Handle, (int)0x0115, (int)ScrollBarRequests.SB_THUMBPOSITION, 0);
            }
        }