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

namespace WindowsFormsApplication1
{
    public partial class 文件分割器1 : Form
    {
        //时间：2012-9-6
        //作者：Olive
        //功能：实现大文件的分割、合并
        #region Members
        int count1,count,fgkDaXiao;
        FileInfo fFenGe,fHeBing;
        FileStream fStream,hStream;
        string fenGeLuJing,heBingLuJing;
        int value = 0;
        #endregion

        #region Methods
        public 文件分割器1()
        {
            InitializeComponent();
            skinEngine1.SkinFile = "WarmColor1.ssk";
        }
        
        /// <summary>
        ///   选择要分割的文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnfgwenjian_Click(object sender, EventArgs e)
        {
            try
            {
                if (openFileDialog1.ShowDialog() == DialogResult.OK)
                {
                    fFenGe = new FileInfo(openFileDialog1.FileName);
                    txtfenge.Text = fFenGe.FullName;

                    fenGeLuJing = fFenGe.FullName.Substring(0, fFenGe.FullName.Length - openFileDialog1.SafeFileName.Length);
                    txtwjdaxiao.Text = ((int)fFenGe.Length/1024).ToString();
                    fStream = new FileStream(fFenGe.FullName, FileMode.Open, FileAccess.Read);
                }
            }
            catch
            {
                MessageBox.Show("文件分割异常，请检查确认无误后再次分割！"); 
            }

        }
        /// <summary>
        /// 选择要保存的路径，如果不选默认为与原文件同路径
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnfglujing_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(txtfgkdaxiao.Text))
            {
                MessageBox.Show("请输入文件分割块大小！");
            }
            if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
            {
               txtfglujing.Text= folderBrowserDialog1.SelectedPath;
               fenGeLuJing = folderBrowserDialog1.SelectedPath+"\\";
            }
        }   
        /// <summary>
        /// 分割文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnfenge_Click(object sender, EventArgs e)
        {
            try
            {
                int wenJianLength = Convert.ToInt32(txtwjdaxiao.Text);

                if (wenJianLength % fgkDaXiao == 0)
                {
                    count = wenJianLength / fgkDaXiao;
                }
                else
                {
                    count = wenJianLength / fgkDaXiao + 1;
                }
                for (int i = 0; i < count; i++)
                {
                    Thread thread = new Thread(new ParameterizedThreadStart(FenGe));
                    thread.Start(i);
                }
                MessageBox.Show("文件分割完毕");
            }
            catch
            {
                MessageBox.Show("分割异常，请确认操作！");
            }
        }
        /// <summary>
        /// 分割线程调用函数
        /// </summary>
        /// <param name="i"></param>
        public void FenGe(object i)
        {

            try
            {
                using (FileStream fgstream = new FileStream(fenGeLuJing + fFenGe.Name.Substring(0, fFenGe.Name.Length - fFenGe.Extension.Length) + i + fFenGe.Extension, FileMode.OpenOrCreate, FileAccess.Write))
                {
                    byte[] buffer = new byte[fgkDaXiao * 1024];
                    int data = 0;
                    if ((data = fStream.Read(buffer, 0, buffer.Length)) > 0)
                    {
                        BinaryWriter bWriter = new BinaryWriter(fgstream, Encoding.Default);
                        bWriter.Write(buffer, 0, data);
                        value=(int)i/count*100;
                        progressBar1.Value = value;
                    }
                    
                }
            }
            catch
            {
                MessageBox.Show("文件打开异常！");
            }

        }
        /// <summary>
        /// 输入值变化
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void txtfgkdaxiao_TextChanged(object sender, EventArgs e)
        {
            if (txtfgkdaxiao.Text.Length > 0)
            {
                fgkDaXiao = Convert.ToInt32(txtfgkdaxiao.Text);
            }
        }
        /// <summary>
        /// 选择要合并的文件，首个分割文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnhbwenjian_Click(object sender, EventArgs e)
        {
            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                fHeBing = new FileInfo(openFileDialog1.FileName);
                txthebing.Text = fHeBing.FullName;
                heBingLuJing = fHeBing.FullName.Substring(0, fHeBing.FullName.Length - openFileDialog1.SafeFileName.Length) + "\\";
            }
        }
        /// <summary>
        /// 选择合并后的文件的保存路径
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnhebinglujing_Click(object sender, EventArgs e)
        {
            if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
            {
                heBingLuJing = folderBrowserDialog1.SelectedPath + "\\";
            }
        }
        /// <summary>
        /// 合并文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                if (count1 > 0)
                {
                    using (hStream = new FileStream(heBingLuJing + fHeBing.Name.Substring(0, fHeBing.Name.Length - fHeBing.Extension.Length - 1) + fHeBing.Extension, FileMode.OpenOrCreate, FileAccess.Write))
                    {
                        for (int i = 0; i < count1; i++)
                        {
                            Thread thread = new Thread(new ParameterizedThreadStart(HeBing));
                            thread.Start(i);
                        }

                        MessageBox.Show("合并完成");
                    }
                }
                else
                {
                    MessageBox.Show("请输入合并文件数目");
                }
            }
            catch
            {
                MessageBox.Show("合并异常，请重新合并");
            }
        }    
        /// <summary>
        /// 求要合并的文件数
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void txthbkuaishu_TextChanged(object sender, EventArgs e)
        {
            count1 = Convert.ToInt32(txthbkuaishu.Text);
        }
        /// <summary>
        /// 合并线程调用的合并函数，执行文件合并
        /// </summary>
        /// <param name="i"></param>
        public void HeBing(object i)
        {
            using (FileStream readStream = new FileStream(fHeBing.FullName.Substring(0, fHeBing.FullName.Length - fHeBing.Extension.Length- 1) + i + fHeBing.Extension, FileMode.Open, FileAccess.Read))
            {
                byte[] buffer = new byte[readStream.Length];
                int data = 0;
                if ((data = readStream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    BinaryWriter binary = new BinaryWriter(hStream, Encoding.Default);
                    binary.Write(buffer, 0, data);
                }
            }
        }
        #endregion
    }
}
                                                   
本文主要用到了FileStream、FileInfo类、BinaryWriter、StreamReader、StreamWriter等常用文件操作类，而且还用到了线程的知识，如果有不懂的地方，希望可以和我交流，共同学习进步