【向zgke提问】打印panel控件问题

using System;

using System.Collections.Generic;

using System.Drawing;

using System.ComponentModel;

using System.Drawing.Imaging;

using System.Drawing.Printing;

using System.Reflection;

using System.Runtime.InteropServices;

using System.Windows.Forms;

using System.Text;



namespace jamonitor

{

    class PrintPanel

    {

        #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

        [System.Runtime.InteropServices.DllImport("gdi32.dll")]

        public static extern long BitBlt(IntPtr HDest, int nXDest, int nYDest, int nWidth, int hHeight, IntPtr HSrc, int nXSrc, int nYSrc, int DwRop);



        private static Bitmap bitMap = null;  //实例化一个位图

        private static System.Drawing.Printing.PrintDocument printDoc = new System.Drawing.Printing.PrintDocument();  //实例化一个打印的对象

        public static void GetPanel(Panel p)

        {         

            MoveBar(0, 0, p);  //下面的方法

            MoveBar(1, 0, p);   //下面的方法

            Point pit = GetScrollPoint(p); //下面的方法

            p.Width += pit.X + 5;   //滚动条的宽

            p.Height += pit.Y + 5;  //滚动条的高

            bitMap = new Bitmap(p.Width, p.Height);         //根据画布的宽和高赋值给位图 

            p.DrawToBitmap(bitMap, new Rectangle(0, 0, bitMap.Width, bitMap.Height));  

            PrintPreviewDialog ppvw = new PrintPreviewDialog();  //初始化一个打印预览

            ppvw.Width = 800;                                    //设置预览的宽

            ppvw.Height = 600;                                   //设置预览的高

            ppvw.Document = printDoc;                            // 预览的文档赋值发送给打印机

            printDoc.DefaultPageSettings.Landscape = false; //是否为纵向打印

            printDoc.PrintPage += new System.Drawing.Printing.PrintPageEventHandler(PrintDoc_PrintPage);  //打印之前发生的事

            PaperSize pp = null;                                                 //定义纸张大小为空

            foreach (PaperSize ps in ppvw.Document.PrinterSettings.PaperSizes)  //获取该打印机支持的纸张大小

            {

                if (ps.PaperName.Equals("A3"))                                 //这里设置纸张大小,但必须是定义好的   

                    pp = ps;

            }

            ppvw.Document.DefaultPageSettings.PaperSize = pp;                  //设置纸张的大小为A3

            if (ppvw.ShowDialog() != DialogResult.OK)                          //如果不打印的话，返回

            {

                printDoc.PrintPage -= new System.Drawing.Printing.PrintPageEventHandler(PrintDoc_PrintPage);

                return;

            }

            printDoc.Print();                                                  //开始打印

        }



        /// <summary>

        /// 打印

        /// </summary>

        /// <param name="sender"></param>

        /// <param name="e"></param>

        private static void PrintDoc_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)

        {

            e.Graphics.DrawImage(bitMap, 0, 0);   //绘制一幅图片

        }



        /// <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);

            }

        }

    }

}