根据文件大小显示文件复制进度条

初学者，照着书上的抄袭制作，但已经理解了里面的意思和应用,并且进行了稍微改善和异常捕捉。这里记录下，以防以后用到这方面的知识点。

窗体设计：

code:

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

    namespace CopyProgress015
    {
        public partial class Form1 : Form
        {
            public Form1()
            {
                InitializeComponent();
            }
            private Thread thdCopyFile; //创建一个线程
            private string str = "";  //用来记录源文件的名字
            FileStream FormerOpenStream;  //实例化源文件FileStream类
            FileStream ToFileOpenStream;  //实例化目标文件FileStream类


            #region //复制文件 函数
            /// <summary>
            /// 复制文件
            /// </summary>
            /// <param name="FormerFile">源文件路径</param>
            /// <param name="ToFile">目的文件路径</param>
            /// <param name="TranSize">传输大小</param>
            /// <param name="progressBar1">ProgressBar控件</param>
            public void CopyFile(string FormerFile, string ToFile, int TranSize, ProgressBar progressBar1)
            {
                progressBar1.Value = 0;//设置进度条的当前位置为0
                progressBar1.Minimum = 0; //设置进度条的最小值为0

                try
                {
                    FormerOpenStream = new FileStream(FormerFile, FileMode.Open, FileAccess.Read);//以只读方式打开源文件
                }
                catch (IOException ex)
                {
                    MessageBox.Show(ex.Message);
                    return;
                }

                try
                {
                    FileStream fileToCreate = new FileStream(ToFile, FileMode.Create); //创建目的文件，如果已存在将被覆盖
                    fileToCreate.Close();//关闭所有fileToCreate的资源
                    fileToCreate.Dispose();//释放所有fileToCreate的资源
                }
                catch(IOException ex)
                {
                    MessageBox.Show(ex.Message);
                    return;
                }


               ToFileOpenStream = new FileStream(ToFile, FileMode.Append, FileAccess.Write);//以写方式打开目的文件


               int max = Convert.ToInt32(Math.Ceiling((Double)FormerOpenStream.Length / (Double)TranSize));//根据一次传输的大小，计算最大传输个数. Math.Ceiling 方法 (Double),返回大于或等于指定的双精度浮点数的最小整数值。

                progressBar1.Maximum = max;//设置进度条的最大值
                int FileSize; //每次要拷贝的文件的大小
                if (TranSize < FormerOpenStream.Length)  //如果分段拷贝，即每次拷贝内容小于文件总长度
                {
                    byte[] buffer = new byte[TranSize]; //根据传输的大小，定义一个字节数组，用来存储传输的字节
                    int copied = 0;//记录传输的大小
                    int tem_n = 1;//设置进度栏中进度的增加个数
                    while (copied <= ((int)FormerOpenStream.Length - TranSize))
                    {
                        FileSize = FormerOpenStream.Read(buffer, 0, TranSize);//从0开始读到buffer字节数组中，每次最大读TranSize
                        FormerOpenStream.Flush();   //清空缓存
                        ToFileOpenStream.Write(buffer, 0, TranSize); //向目的文件写入字节
                        ToFileOpenStream.Flush();//清空缓存
                        ToFileOpenStream.Position = FormerOpenStream.Position; //是源文件的目的文件流的位置相同
                        copied += FileSize; //记录已经拷贝的大小
                        progressBar1.Value = progressBar1.Value + tem_n; //增加进度栏的进度块
                    }
                    int leftSize = (int)FormerOpenStream.Length - copied; //获取剩余文件的大小
                    FileSize = FormerOpenStream.Read(buffer, 0, leftSize); //读取剩余的字节
                    FormerOpenStream.Flush();
                    ToFileOpenStream.Write(buffer, 0, leftSize); //写入剩余的部分
                    ToFileOpenStream.Flush();
                }
                else //如果整体拷贝，即每次拷贝内容大于文件总长度
                {
                    byte[] buffer = new byte[FormerOpenStream.Length];
                    FormerOpenStream.Read(buffer, 0, (int)FormerOpenStream.Length);
                    FormerOpenStream.Flush();
                    ToFileOpenStream.Write(buffer, 0, (int)FormerOpenStream.Length);
                    ToFileOpenStream.Flush();

                }
                FormerOpenStream.Close();
                ToFileOpenStream.Close();
                if (MessageBox.Show("copy finished") == DialogResult.OK)
                {
                    progressBar1.Value = 0;
                    txtOriginalFile.Clear();
                    txtCopyFile.Clear();
                    str = "";

                }

            }

            #endregion



            public delegate void CopyFile_Delegate(); //定义委托/托管线程
            /// <summary>
            /// 在线程上执行委托（设置托管线程函数）
            /// </summary>
            public void SetCopyFile()
            {
                //this.Invoke(new CopyFile_Delegate(RunCopyFile)); //对指定的线程进行托管
                //下面两行代码等同上面一行代码
                CopyFile_Delegate copyfile_delegate = new CopyFile_Delegate(RunCopyFile); //创建delegate对象
                this.Invoke(copyfile_delegate); //调用delegate            
            }


            /// <summary>
            /// 设置线程，运行copy文件，它与代理CopyFile_Delegate应具有相同的参数和返回类型
            /// </summary>
            public void RunCopyFile()
            {
                CopyFile(txtOriginalFile.Text, txtCopyFile.Text + "\" + str, 1024, progressBar1); //复制文件
                Thread.Sleep(0); //避免假死 
                thdCopyFile.Abort();  //关闭线程

            }


            private void btnOriginalFile_Click(object sender, EventArgs e)
            {
                if (openFileDialog1.ShowDialog() == DialogResult.OK)  //打开文件对话框
                {
                    txtOriginalFile.Text = openFileDialog1.FileName;  //获取源文件的路径
                }

            }

            private void btnCopyFile_Click(object sender, EventArgs e)
            {
                if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
                {
                    txtCopyFile.Text = folderBrowserDialog1.SelectedPath;//获取目的文件的路径               
                }
            }


            private void btnBeginToCopy_Click(object sender, EventArgs e)
            {                    
            
                if (txtOriginalFile.Text.Trim() == string.Empty)
                {
                    MessageBox.Show("OriginalFile cannot be empty!");
                    return;
                
                }
                else
                {
                    str = txtOriginalFile.Text;//记录源文件的路径
                    str = str.Substring(str.LastIndexOf('\') + 1, str.Length - str.LastIndexOf('\') - 1); //获取源文件的名称
                }


                if (txtCopyFile.Text.Trim() == string.Empty)
                {
                    MessageBox.Show("The Copyfile path cannot be empty!");
                    return;
                }
                else
                {
                    thdCopyFile = new Thread(new ThreadStart(SetCopyFile));
                    thdCopyFile.Start();
                }             
            
            }


            /// <summary>
            /// 给textbox增加tooltip
            /// </summary>
            /// <param name="sender"></param>
            /// <param name="e"></param>
            private void txtOriginalFile_MouseHover(object sender, EventArgs e)
            {
                ToolTip tooltip = new ToolTip();
                if (txtOriginalFile.Text.Trim() != string.Empty)
                {
                    
                    tooltip.Show(txtOriginalFile.Text, txtOriginalFile);
                }
                else
                {
                    tooltip.Hide(txtOriginalFile);
                }
                
            }
            /// <summary>
            /// 给textbox增加tooltip
            /// </summary>
            /// <param name="sender"></param>
            /// <param name="e"></param>
            private void txtCopyFile_MouseHover(object sender, EventArgs e)
            {
                ToolTip tooltip = new ToolTip();
                if (txtCopyFile.Text.Trim() != string.Empty)
                {
                    
                    tooltip.Show(txtCopyFile.Text, txtCopyFile);
                }
                else
                {
                    tooltip.Hide(txtCopyFile); 
                }

            }

        }
    }