在做项目的时候需要将文件进行压缩和解压缩，于是就从http://www.icsharpcode.net下载了关于压缩和解压缩的源码，但是下载下来后，面对这么多的代码，一时不知如何下手。只好耐下心来，慢慢的研究，总算找到了门路。针对自己的需要改写了文件压缩和解压缩的两个类，分别为ZipClass和UnZipClass。其中碰到了不少困难，就决定写出来压缩和解压的程序后，一定把源码贴出来共享，让首次接触压缩和解压缩的朋友可以少走些弯路。下面就来解释如何在C#里用http://www.icsharpcode.net下载的SharpZipLib进行文件的压缩和解压缩。
    首先需要在项目里引用SharpZipLib.dll。然后修改其中的关于压缩和解压缩的类。实现源码如下：

/// <summary>
/// 压缩文件
/// </summary>

using System;
using System.IO;

using ICSharpCode.SharpZipLib.Checksums;
using ICSharpCode.SharpZipLib.Zip;
using ICSharpCode.SharpZipLib.GZip;

namespace Compression
{
public class ZipClass
{

  public void ZipFile(string FileToZip, string ZipedFile ,int CompressionLevel, int BlockSize)
  {
  //如果文件没有找到，则报错
  if (! System.IO.File.Exists(FileToZip))
  {
    throw new System.IO.FileNotFoundException(The specified file + FileToZip + could not be found. Zipping aborderd);
  }
 
  System.IO.FileStream StreamToZip = new System.IO.FileStream(FileToZip,System.IO.FileMode.Open , System.IO.FileAccess.Read);
  System.IO.FileStream ZipFile = System.IO.File.Create(ZipedFile);
  ZipOutputStream ZipStream = new ZipOutputStream(ZipFile);
  ZipEntry ZipEntry = new ZipEntry(ZippedFile);
  ZipStream.PutNextEntry(ZipEntry);
  ZipStream.SetLevel(CompressionLevel);
  byte[] buffer = new byte[BlockSize];


System.Int32 size =StreamToZip.Read(buffer,0,buffer.Length);
  ZipStream.Write(buffer,0,size);
  try
  {
    while (size < StreamToZip.Length)
    {
    int sizeRead =StreamToZip.Read(buffer,0,buffer.Length);
    ZipStream.Write(buffer,0,sizeRead);
    size += sizeRead;
    }
  }
  catch(System.Exception ex)
  {
    throw ex;
  }
  ZipStream.Finish();
  ZipStream.Close();
  StreamToZip.Close();
  }

  public void ZipFileMain(string[] args)
  {
  string[] filenames = Directory.GetFiles(args[0]);
 
  Crc32 crc = new Crc32();

ZipOutputStream s = new ZipOutputStream(File.Create(args[1]));
 
  s.SetLevel(6); // 0 - store only to 9 - means best compression
 
  foreach (string file in filenames)
  {
    //打开压缩文件
    FileStream fs = File.OpenRead(file);
 
    byte[] buffer = new byte[fs.Length];
    fs.Read(buffer, 0, buffer.Length);
    ZipEntry entry = new ZipEntry(file);
 
    entry.DateTime = DateTime.Now;
 
    // set Size and the crc, because the information
    // about the size and crc should be stored in the header
    // if it is not set it is automatically written in the footer.
    // (in this case size == crc == -1 in the header)
    // Some ZIP programs have problems with zip files that don't store
    // the size and crc in the header.
    entry.Size = fs.Length;
    fs.Close();
 
    crc.Reset();

crc.Update(buffer);
 
    entry.Crc  = crc.Value;
 
    s.PutNextEntry(entry);
 
    s.Write(buffer, 0, buffer.Length);
 
  }
 
  s.Finish();
  s.Close();
  }
}
}

现在再来看看解压文件类的源码

/// <summary>
/// 解压文件
/// </summary>

using System;
using System.Text;
using System.Collections;
using System.IO;
using System.Diagnostics;
using System.Runtime.Serialization.Formatters.Binary;
using System.Data;

using ICSharpCode.SharpZipLib.BZip2;
using ICSharpCode.SharpZipLib.Zip;
using ICSharpCode.SharpZipLib.Zip.Compression;



using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
using ICSharpCode.SharpZipLib.GZip;

namespace DeCompression
{
public class UnZipClass
{ 
  public void UnZip(string[] args)
  {
  ZipInputStream s = new ZipInputStream(File.OpenRead(args[0]));
 
  ZipEntry theEntry;
  while ((theEntry = s.GetNextEntry()) != null)
  {
 
          string directoryName = Path.GetDirectoryName(args[1]);
    string fileName      = Path.GetFileName(theEntry.Name);
 
    //生成解压目录
    Directory.CreateDirectory(directoryName);
 
    if (fileName != String.Empty)
    { 
    //解压文件到指定的目录
    FileStream streamWriter = File.Create(args[1]+theEntry.Name);
   
    int size = 2048;


byte[] data = new byte[2048];
    while (true)
    {
      size = s.Read(data, 0, data.Length);
      if (size > 0)
      {
      streamWriter.Write(data, 0, size);
      }
      else
      {
      break;
      }
    }
   
    streamWriter.Close();
    }
  }
  s.Close();
  }
}
}

    有了压缩和解压缩的类以后，就要在窗体里调用了。怎么？是新手，不会调用？Ok,接着往下看如何在窗体里调用。

    首先在窗体里放置两个命令按钮（不要告诉我你不会放啊~），然后编写以下源码

/// <summary>
/// 调用源码
/// </summary>

      private void button2_Click_1(object sender, System.EventArgs e)
  {
  string []FileProperties=new string[2];


FileProperties[0]=C:\\unzipped\\;//待压缩文件目录
  FileProperties[1]=C:\\zip\\a.zip;  //压缩后的目标文件
  ZipClass Zc=new ZipClass();
  Zc.ZipFileMain(FileProperties);
  }

    private void button2_Click(object sender, System.EventArgs e)
  {
  string []FileProperties=new string[2];
  FileProperties[0]=C:\\zip\\test.zip;//待解压的文件
  FileProperties[1]=C:\\unzipped\\;//解压后放置的目标目录
  UnZipClass UnZc=new UnZipClass();
  UnZc.UnZip(FileProperties);
  }