c# 大文件分割复制 Filestream 进度条

大文件分割复制，每次复制100M 也可以复制别的较大数值。

小于1G的小文件就直接复制得了。代码里没写，但是很简单直接写进去就好了，难得是分割复制所以没写. 好吧我还是改了改成小文件也可以复制了，全面一点是不

效果图【图片里的总文件大小忘记除1024了。文章里的代码改了，图片和源代码文件改了】

代码写得不是很好.请多多指教

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FileStrem大文件分割复制
{
    public partial class Form1 : Form
    {
        private int WriterByetNub = 104857600;//100M复制速度
        //源目标
        private FileStream FileToRead;
        //复制到文件
        private FileStream FileToWrite;
        //保存文件的地址
        private string SaveFile_Add;
        //源文件的名字
        private string File_Add;
        //设置正常写入字节
        private Byte[] byteToWrite;
        //设置剩余写入字节
        private Byte[] byteToLastWrite;
        //循环次数
        private long WriteTimes;
        //循环后的剩余字节
        private int L_Size;

        public Form1()
        {
            InitializeComponent();
        }
        //设置委托
        private delegate void OpenFile();

        private void Cpy()
        {
            try
            {
                label_Add.Text = "源地址";

                label_Cpy_Add.Text = "复制到";

                label_Cpy_Lc.Text = "复制进程:";

                label_Write.Text = "已经写入";

                label_FileSize.Text = "源文件总大小";
                //文件选取
                OpenFileDialog openfileDialog = new OpenFileDialog();
                //show文件选取器
                openfileDialog.ShowDialog();

                File_Add = openfileDialog.FileName;

                label_Add.Text += "：" + File_Add;
                
                //保存地址选取
                FolderBrowserDialog savefileDialog = new FolderBrowserDialog();

                savefileDialog.ShowDialog();

                SaveFile_Add = savefileDialog.SelectedPath;

                label_Cpy_Add.Text += "：" + SaveFile_Add + File_Add;

                FileToRead = new FileStream(File_Add, FileMode.Open, FileAccess.Read);

                FileToWrite = new FileStream(@SaveFile_Add + "\\" + openfileDialog.SafeFileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);

                label_FileSize.Text = "源文件总大小"+(FileToRead.Length/1024).ToString()+"KB";
                if (FileToRead.Length > WriterByetNub)
                //设置写入字节数组
                {
                    byteToWrite = new byte[WriterByetNub];
                    //循环次数
                    WriteTimes = FileToRead.Length / WriterByetNub;
                    //多次循环后剩余字节
                    L_Size = Convert.ToInt32(FileToRead.Length % WriterByetNub);
                    //多次循环后字节数组
                    byteToLastWrite = new byte[L_Size];

                    for (long i = 0; i <= WriteTimes; i++)
                    {
                        //读源文件
                        FileToRead.Read(byteToWrite, 0, WriterByetNub);

                        //写数据到目标文件
                        FileToWrite.Write(byteToWrite, 0, WriterByetNub);

                        //设置进度条的值
                        progressBar.Value = Convert.ToInt32(i * 100 / WriteTimes);

                        Application.DoEvents();

                        //设置Lable上的进度值
                        label_Cpy_Lc.Text = "复制进程:" + Convert.ToInt32((i * 100) / WriteTimes).ToString() + "%";

                        //设置写入值
                        label_Write.Text = "已写入" + (FileToRead.Position / 1024).ToString() + "KB";
                    }

                    //剩余字节的读和写
                    if (L_Size != 0)
                    {
                        FileToRead.Read(byteToLastWrite, 0, L_Size);

                        FileToWrite.Write(byteToLastWrite, 0, L_Size);
                    }
                }
                else //当写于分割的字节大小时 直接复制吧

                {
                    //设置进度条的最大值
                    progressBar.Maximum =(int) FileToRead.Length;
                    //设置字节
                    byteToWrite = new byte[FileToRead.Length];
                    //读取到字节中
                    FileToRead.Read(byteToWrite, 0, (int)FileToRead.Length);
                    //计算进程
                    label_Cpy_Lc.Text = "复制进程:" + Convert.ToInt32(FileToRead.Position/FileToRead.Length*100).ToString() + "%";

                    //设置写入值
                    label_Write.Text = "已写入" + (FileToRead.Position / 1024).ToString() + "KB";
                    //计算进度条的进度
                    progressBar.Value =(int )FileToRead.Position;
                    //写入完成
                    FileToWrite.Write(byteToWrite, 0, (int)FileToRead.Length);                   
                }
                FileToRead.Flush();

                FileToWrite.Flush();

                FileToRead.Close();

                FileToWrite.Close();

                MessageBox.Show("复制完成");
            }
            catch(Exception ex)

            {
                FileToRead.Flush();

                FileToWrite.Flush();

                FileToRead.Close();

                FileToWrite.Close();

                MessageBox.Show(ex.ToString());
               
            }
        }

        private void openFileBtn_Click(object sender, EventArgs e)
        {
            OpenFile getFile = new OpenFile(Cpy);
            this.Invoke(getFile);
        }
    }
}