C# 学习黑马.Net视频教程，大文件拷贝

设计器代码：

namespace 大文件拷贝
{
    partial class Form1
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.textBox2 = new System.Windows.Forms.TextBox();
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.button3 = new System.Windows.Forms.Button();
            this.button4 = new System.Windows.Forms.Button();
            this.progressBar1 = new System.Windows.Forms.ProgressBar();
            this.label1 = new System.Windows.Forms.Label();
            this.label2 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(28, 12);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(299, 21);
            this.textBox1.TabIndex = 0;
            // 
            // textBox2
            // 
            this.textBox2.Location = new System.Drawing.Point(28, 51);
            this.textBox2.Name = "textBox2";
            this.textBox2.Size = new System.Drawing.Size(299, 21);
            this.textBox2.TabIndex = 0;
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(334, 10);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(64, 23);
            this.button1.TabIndex = 1;
            this.button1.Text = "源文件";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // button2
            // 
            this.button2.Location = new System.Drawing.Point(334, 49);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(64, 23);
            this.button2.TabIndex = 1;
            this.button2.Text = "保存到";
            this.button2.UseVisualStyleBackColor = true;
            this.button2.Click += new System.EventHandler(this.button2_Click);
            // 
            // button3
            // 
            this.button3.Location = new System.Drawing.Point(40, 89);
            this.button3.Name = "button3";
            this.button3.Size = new System.Drawing.Size(140, 48);
            this.button3.TabIndex = 2;
            this.button3.Text = "1个1个字节拷贝";
            this.button3.UseVisualStyleBackColor = true;
            this.button3.Click += new System.EventHandler(this.button3_Click);
            // 
            // button4
            // 
            this.button4.Location = new System.Drawing.Point(228, 89);
            this.button4.Name = "button4";
            this.button4.Size = new System.Drawing.Size(132, 48);
            this.button4.TabIndex = 2;
            this.button4.Text = "大文件拷贝";
            this.button4.UseVisualStyleBackColor = true;
            this.button4.Click += new System.EventHandler(this.button4_Click);
            // 
            // progressBar1
            // 
            this.progressBar1.Location = new System.Drawing.Point(28, 164);
            this.progressBar1.Name = "progressBar1";
            this.progressBar1.Size = new System.Drawing.Size(350, 23);
            this.progressBar1.Step = 1;
            this.progressBar1.TabIndex = 3;
            // 
            // label1
            // 
            this.label1.AutoSize = true;
            this.label1.Location = new System.Drawing.Point(384, 170);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(17, 12);
            this.label1.TabIndex = 4;
            this.label1.Text = "0%";
            // 
            // label2
            // 
            this.label2.AutoSize = true;
            this.label2.Location = new System.Drawing.Point(26, 203);
            this.label2.Name = "label2";
            this.label2.Size = new System.Drawing.Size(29, 12);
            this.label2.TabIndex = 4;
            this.label2.Text = "0k/s";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(421, 234);
            this.Controls.Add(this.label2);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.progressBar1);
            this.Controls.Add(this.button4);
            this.Controls.Add(this.button3);
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.textBox2);
            this.Controls.Add(this.textBox1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion

        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.TextBox textBox2;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.Button button3;
        private System.Windows.Forms.Button button4;
        private System.Windows.Forms.ProgressBar progressBar1;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.Label label2;
    }
}

代码：

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;

//*************************************************************************************
//**********************黑马程序员/Asp.Net/技术群：118041544 **************************
//*************************************************************************************
namespace 大文件拷贝
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private string _fileName;
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            if (ofd.ShowDialog() == DialogResult.OK)
            {
                this.textBox1.Text = ofd.FileName;
                _fileName = ofd.SafeFileName;
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {
            FolderBrowserDialog fbd = new FolderBrowserDialog();
            if (fbd.ShowDialog() == DialogResult.OK)
            {
                this.textBox2.Text = fbd.SelectedPath;
            }
        }

        private void button3_Click(object sender, EventArgs e)
        {
            this.progressBar1.Value = 0;
            this.label1.Text = "0%";
            if (!File.Exists(this.textBox1.Text))
            {
                MessageBox.Show("找不到目标文件！");
                return;
            }
            if (!Directory.Exists(this.textBox2.Text))
            {
                MessageBox.Show("请选择有效的保存路径！");
                return;
            }
            string fileRead = this.textBox1.Text;
            string fileSave = this.textBox2.Text + "/" + _fileName;

            System.Threading.ThreadPool.QueueUserWorkItem((o) =>
            {
                using (IDisposable file = new FileStream(fileRead, FileMode.Open, FileAccess.Read),
                fileWrite = new FileStream(fileSave, FileMode.Create, FileAccess.Write))
                {
                    int count = 0;
                    long fileLength = ((FileStream)file).Length; //目标文件大小
                    double n = (100 * 1.0 / fileLength);  //每次进度条累加
                    double m = 0;                         //累加统计
                    int spam = 1;                         //时间间隔
                    double speed = 0;                     //拷贝速度

                    do
                    {
                        DateTime time = DateTime.Now;
                        count = ((FileStream)file).ReadByte();
                        ((FileStream)fileWrite).WriteByte((byte)count);//按一个字节一个字节写入
                        //计算速度 单位k/s 
                        speed = (1.0 * 1000 / 1024) / spam;

                        //进度条
                        m = m + n;

                        //控件显示
                        ShowProbar(o, m, speed);

                        //保存时间间隔，单位毫秒
                        spam = (DateTime.Now - time).Milliseconds > 0 ? (DateTime.Now - time).Milliseconds : spam;//必须大于0

                    } while (count != -1);
                }
                if (this.progressBar1.Value == 100)
                {
                    System.Threading.Thread.Sleep(1000); //延迟1秒弹出
                    MessageBox.Show("拷贝成功！");
                }
            });
        }

        private void button4_Click(object sender, EventArgs e)
        {
            this.progressBar1.Value = 0;
            this.label1.Text = "0%";
            if (!File.Exists(this.textBox1.Text))
            {
                MessageBox.Show("找不到目标文件！");
                return;
            }
            if (!Directory.Exists(this.textBox2.Text))
            {
                MessageBox.Show("请选择有效的保存路径！");
                return;
            }
            string fileRead = this.textBox1.Text;
            string fileSave = Path.Combine(this.textBox2.Text, _fileName);
            System.Threading.ThreadPool.QueueUserWorkItem((o) =>
            {
                using (IDisposable file = new FileStream(fileRead, FileMode.Open, FileAccess.Read),
                    fileWrite = new FileStream(fileSave, FileMode.Create, FileAccess.Write))
                {
                    int count = 0;
                    long fileLength =((FileStream)file).Length; //目标文件大小
                    //根据目标文件大小创建byte数组长度
                    byte[] data = new byte[fileLength > 1024 * 1024 * 30 ? 1024 * 1024 * 30 : fileLength]; //30M 1024 * 1024 * 30
                    int step = (int)Math.Ceiling(fileLength * 1.0 / data.Length); //分流段数
                    double n = (100 * 1.0 / step);  //每次进度条累加
                    double m = 0;                   //累加统计
                    int spam = 1;                   //时间间隔
                    double speed = 0;               //拷贝速度
                    do
                    {
                        DateTime time = DateTime.Now;
                        //文件流操作
                        count = ((FileStream)file).Read(data, 0, data.Length);
                        ((FileStream)fileWrite).Write(data, 0, count);

                        //保存时间间隔，单位毫秒
                        spam = (DateTime.Now - time).Milliseconds > 0 ? (DateTime.Now - time).Milliseconds : spam;//必须大于0

                        //计算速度 单位k/s 
                        if (count == data.Length)
                        {
                            speed = (count * 1.0 / 1024 / spam) * 1000;
                        }

                        //进度条
                        m = m + n;

                        //控件显示
                        ShowProbar(o, m, speed);
                        
                    } while (count > 0);  
                }
                if (this.progressBar1.Value == 100)
                {
                    System.Threading.Thread.Sleep(1000); //延迟1秒弹出
                    MessageBox.Show("拷贝成功！");
                }
            });
        }

        private void ShowProbar(object o, double m, double speed)
        {
            try
            {
                int barValue = (int)Math.Floor(m) >= 100 ? 100 : (int)Math.Floor(m);

                this.Invoke((MethodInvoker)(() =>
                {
                    this.progressBar1.Value = barValue;
                    this.label1.Text = barValue.ToString() + "%";
                    this.label2.Text = speed >= 1024 ? (speed / 1024).ToString("0.0m/s") : (speed >= 1 ? speed.ToString("0k/s") : (speed * 1024).ToString("0b/s"));
                }));
            }
            catch (Exception e)
            {
                throw new Exception(e.Message);
            }
        }
    }
}