c# 封装的图像类和自己bitmap类关联

作业，之前就会一点c++,老师给了底模板，他自己写了一个classImages类~让我们在上面加代码，但是让人郁闷的是写的程序貌似在构造函数中加载一副图片，但是我不想这么做~ 我想通过一个打开的菜单控件自己打开所需要的图像，再在panel上面画，相关资料用system.draeing.bitmap建一个对象，图像是通过这个对象传进来的~我想问一下怎么把这个对象和写的ClassIMge这个类关联起来？？纠结很久了。。。就是弄不出来~ 恳请大侠们帮帮忙。。。。
这是主form：

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;



namespace DIPcSharp

{

    public partial class MainForm : Form

    {

        ClassImage mImage;

        bool hasHist;



        public MainForm()

        {

            InitializeComponent();

            mImage = new ClassImage();

            mImage.ReadImage("E:\\oop\\lena.jpg");

            hasHist = false;

        }



        private void ImagePanel_Paint(object sender, PaintEventArgs e)

        {

            mImage.Display(e.Graphics, ImagePanel.Width, ImagePanel.Height);

            if (hasHist) mImage.drawHist(e.Graphics);

        }

        private void 打开ToolStripMenuItem_Click(object sender, EventArgs e)

        {

            OpenFileDialog opnDlg = new OpenFileDialog();

            opnDlg.Filter = "所有图像文件|*.bmp;*.pcx;*.png;*.jpg;*.gif;";

            opnDlg.Title = "打开图像文件";

            opnDlg.ShowHelp = true;

            if (opnDlg.ShowDialog() == DialogResult.OK)

            {

                curFilename = opnDlg.FileName;//读取文件名

                try

                {

                    curBitmap = (Bitmap)Image.FromFile(curFilename);

                }

                catch (Exception exp)

                {

                    MessageBox.Show(exp.Message);



                }

                Refresh();

            }

        }

    }

}

下面的是老师给的类：

using System;

using System.Collections.Generic;

using System.Text;

using System.Drawing;



namespace DIPcSharp

{

    class ClassImage

    {

        Bitmap BMap;

        int Width, Height, FWidth;

        byte [] ImageB;

        Int32 [] Hist = new Int32[256];

        //int ImageType;



        public int ReadImage(string FileName)

        {

            BMap = new Bitmap(FileName);

            Width = BMap.Width;

            Height = BMap.Height;

            getBitMapData();

            //ImageType = BMap.PixelFormat;

            return 0;

        }



        public int Display(System.Drawing.Graphics e, int w, int h)

        {

            e.DrawImage(BMap, 0, 0, w, h);

            return 0;

        }



        private bool getBitMapData()

        {

            // 从BitMap对象里获取图像数据

            if(BMap == null)  // 图像对象必须存在

            {

                return false;

            };

            Rectangle rect = new Rectangle(0, 0, Width, Height); //' 为锁定图像范围定义矩形

            System.Drawing.Imaging.BitmapData bmpData = BMap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, BMap.PixelFormat);



            //' Get the address of the first line.

            IntPtr ptr = bmpData.Scan0;



            if (BMap.PixelFormat == System.Drawing.Imaging.PixelFormat.Format8bppIndexed)

            {

                FWidth = Convert.ToInt32((BMap.Width + 3) / 4) * 4;

                Int32 bytes = FWidth * BMap.Height;

                ImageB = new byte[bytes];

                System.Runtime.InteropServices.Marshal.Copy(ptr, ImageB, 0, bytes);

            }

            //' Unlock the bits.

            BMap.UnlockBits(bmpData);

            return true;

        }



        private bool putBitMapData()

        {

            if(BMap == null)  // 图像对象必须存在

            {

                return false;

            };

            Rectangle rect = new Rectangle(0, 0, BMap.Width, BMap.Height); //' 为锁定图像范围定义矩形

            System.Drawing.Imaging.BitmapData bmpData = BMap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, BMap.PixelFormat);

            //' Get the address of the first line.

            

            IntPtr ptr = bmpData.Scan0;



            if (BMap.PixelFormat == System.Drawing.Imaging.PixelFormat.Format8bppIndexed)

            {

                Int32 bytes = BMap.Width * BMap.Height;

                System.Runtime.InteropServices.Marshal.Copy(ImageB, 0, ptr, bytes);

            }

            BMap.UnlockBits(bmpData);

            return (true);

        }



        public void Histgram()

        {

            int i, j, bytes;



            for (i = 0; i < 256; i++) Hist[i] = 0;

            for (i = 0; i < Height; i++)

                for (j = 0; j < Width; j++)

                {

                    bytes = i * FWidth + j;

                    Hist[ImageB[bytes]]++;

                }

            return;

        }



        public void drawHist(System.Drawing.Graphics e)

        {

            int i;

            double maxH;

            maxH = Hist[0];

            for (i = 1; i < 256; i++)

                if (maxH < Hist[i]) maxH = Hist[i];

            //Brush b =new Brush;

            maxH = maxH * 1.2;

            Pen p = new Pen(Color.Red);

            for (i = 0; i < 255; i++)

                e.DrawLine(p,i*2+20,500-Convert.ToInt32(Convert.ToDouble(Hist[i])/maxH*480)+20,(i+1)*2+20,500-Convert.ToInt32(Convert.ToDouble(Hist[i+1])/maxH*480)+20);

        }



        public bool Negative()

        {

            int i, j;

            for(i=0;i<Height;i++)

            {

                for(j=0;j<Width;j++)

                {

                    ImageB[i * FWidth + j] = Convert.ToByte(255 - ImageB[i * FWidth + j]);

                }

            }

            putBitMapData();

            return(true);

        }

    }

}