C#分割大文件为小文件，同时实现将 已分割的小文件合并

【实例简介】分割大文件为小文件，同时实现将 已分割的小文件合并
【实例截图】

【核心代码】

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;
namespace FileComminuteUnite
{
    public partial class frmSplit : Form
    {
        public frmSplit()
        {
            InitializeComponent();
        }

        #region 分割文件
        /// <summary>
        /// 分割文件
        /// </summary>
        /// <param name="strFlag">分割单位</param>
        /// <param name="intFlag">分割大小</param>
        /// <param name="strPath">分割后的文件存放路径</param>
        /// <param name="strFile">要分割的文件</param>
        /// <param name="PBar">进度条显示</param>
        public void SplitFile(string strFlag, int intFlag, string strPath, string strFile, ProgressBar PBar)
        {
            int iFileSize = 0;
            //根据选择来设定分割的小文件的大小
            switch (strFlag)
            {
                case "Byte":
                    iFileSize = intFlag;
                    break;
                case "KB":
                    iFileSize = intFlag * 1024;
                    break;
                case "MB":
                    iFileSize = intFlag * 1024 * 1024;
                    break;
                case "GB":
                    iFileSize = intFlag * 1024 * 1024 * 1024;
                    break;
            }
            //以文件的全路径对应的字符串和文件打开模式来初始化FileStream文件流实例
            FileStream SplitFileStream = new FileStream(strFile, FileMode.Open);
            //以FileStream文件流来初始化BinaryReader文件阅读器
            BinaryReader SplitFileReader = new BinaryReader(SplitFileStream);
            //每次分割读取的最大数据
            byte[] TempBytes;
            //小文件总数
            int iFileCount = (int)(SplitFileStream.Length / iFileSize);
            PBar.Maximum = iFileCount;
            if (SplitFileStream.Length % iFileSize != 0) iFileCount  ;
            string[] TempExtra = strFile.Split('.');
            //循环将大文件分割成多个小文件
            for (int i = 1; i <= iFileCount; i  )
            {
                //确定小文件的文件名称
                string sTempFileName = strPath   @"\"   i.ToString().PadLeft(4, '0')   "."   TempExtra[TempExtra.Length - 1]; //小文件名
                //根据文件名称和文件打开模式来初始化FileStream文件流实例
                FileStream TempStream = new FileStream(sTempFileName, FileMode.OpenOrCreate);
                //以FileStream实例来创建、初始化BinaryWriter书写器实例
                BinaryWriter TempWriter = new BinaryWriter(TempStream);
                //从大文件中读取指定大小数据
                TempBytes = SplitFileReader.ReadBytes(iFileSize);
                //把此数据写入小文件
                TempWriter.Write(TempBytes);
                //关闭书写器，形成小文件
                TempWriter.Close();
                //关闭文件流
                TempStream.Close();
                PBar.Value = i - 1;
            }
            //关闭大文件阅读器
            SplitFileReader.Close();
            SplitFileStream.Close();
            MessageBox.Show("文件分割成功!");
        }
        #endregion

        #region 合并文件
        /// <summary>
        /// 合并文件
        /// </summary>
        /// <param name="list">要合并的文件集合</param>
        /// <param name="strPath">合并后的文件名称</param>
        /// <param name="PBar">进度条显示</param>
        public void CombinFile(string[] strFile, string strPath, ProgressBar PBar)
        {
            PBar.Maximum = strFile.Length;
            FileStream AddStream = null;
            //以合并后的文件名称和打开方式来创建、初始化FileStream文件流
            AddStream = new FileStream(strPath, FileMode.Append);
            //以FileStream文件流来初始化BinaryWriter书写器，此用以合并分割的文件
            BinaryWriter AddWriter = new BinaryWriter(AddStream);
            FileStream TempStream = null;
            BinaryReader TempReader = null;
            //循环合并小文件，并生成合并文件
            for (int i = 0; i < strFile.Length; i  )
            {
                //以小文件所对应的文件名称和打开模式来初始化FileStream文件流，起读取分割作用
                TempStream = new FileStream(strFile[i].ToString(), FileMode.Open);
                TempReader = new BinaryReader(TempStream);
                //读取分割文件中的数据，并生成合并后文件
                AddWriter.Write(TempReader.ReadBytes((int)TempStream.Length));
                //关闭BinaryReader文件阅读器
                TempReader.Close();
                //关闭FileStream文件流
                TempStream.Close();
                PBar.Value = i   1;
            }
            //关闭BinaryWriter文件书写器
            AddWriter.Close();
            //关闭FileStream文件流
            AddStream.Close();
            MessageBox.Show("文件合并成功！");
        }
        #endregion

        private void frmSplit_Load(object sender, EventArgs e)
        {
            timer1.Start();//启动计时器
        }

        //选择要分割的文件
        private void btnSFile_Click(object sender, EventArgs e)
        {
            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                txtFile.Text = openFileDialog.FileName;
            }
        }

        //执行文件分割操作
        private void btnSplit_Click(object sender, EventArgs e)
        {
            try
            {
                if (txtLength.Text == ""||txtFile.Text.Trim()==""||txtPath.Text.Trim()=="")
                {
                    MessageBox.Show("请将信息填写完整！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    txtLength.Focus();
                }
                else if (cboxUnit.Text == "")
                {
                    MessageBox.Show("请选择要分割的文件单位！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    cboxUnit.Focus();
                }
                else
                {
                    SplitFile(cboxUnit.Text, Convert.ToInt32(txtLength.Text.Trim()), txtPath.Text, txtFile.Text, progressBar);
                }
            }
            catch { }
        }

        //选择分割后的文件存放路径
        private void btnSPath_Click(object sender, EventArgs e)
        {
            if (folderBrowserDialog.ShowDialog() == DialogResult.OK)
            {
                txtPath.Text = folderBrowserDialog.SelectedPath;
            }
        }

        //选择要合成的文件
        private void btnCFile_Click(object sender, EventArgs e)
        {
            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                string Selectfile = "";
                string[] files = openFileDialog.FileNames;
                for (int i = 0; i < files.Length; i  )
                {
                    Selectfile  = ","   files[i].ToString();
                }
                if (Selectfile.StartsWith(","))
                {
                    Selectfile = Selectfile.Substring(1);
                }
                if (Selectfile.EndsWith(","))
                {
                    Selectfile.Remove(Selectfile.LastIndexOf(","),1);
                }
                txtCFile.Text = Selectfile;
            }
        }

        //选择合成后的文件存放路径
        private void btnCPath_Click(object sender, EventArgs e)
        {
            if (saveFileDialog.ShowDialog() == DialogResult.OK)
            {
                txtCPath.Text = saveFileDialog.FileName;
            }
        }

        //执行合成文件操作
        private void btnCombin_Click(object sender, EventArgs e)
        {
            try
            {
                if (txtCFile.Text.Trim() == "" || txtCPath.Text.Trim() == "")
                {
                    MessageBox.Show("请将信息输入完整！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
                else
                {
                    if (txtCFile.Text.IndexOf(",") == -1)
                        MessageBox.Show("请选择要合成的文件，最少为两个！", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
                    else
                    {
                        string[] strFiles = txtCFile.Text.Split(',');
                        CombinFile(strFiles, txtCPath.Text, progressBar);
                    }
                }
            }
            catch { }
        }

        //监视“分割”/“合并”按钮的可用状态
        private void timer1_Tick(object sender, EventArgs e)
        {
            if (txtFile.Text != "" && txtPath.Text != "")
                btnSplit.Enabled = true;
            else
                btnSplit.Enabled = false;
            if (txtCFile.Text != "" && txtCPath.Text != "")
                btnCombin.Enabled = true;
            else
                btnCombin.Enabled = false;
        }
    }
}