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);
  }