本文實例講述了asp.net C#實現(xiàn)解壓縮文件的方法，需要引用一個ICSharpCode.SharpZipLib.dll，供大家參考，具體如下：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using ICSharpCode.SharpZipLib.Zip;

using System.IO;

using ICSharpCode.SharpZipLib.Checksums;

using System.Web;

namespace Mvc51Hiring.Common.Tool

{

  /// <summary> <br>  /// 作者：來自網(wǎng)格<br>  /// 修改人:sunkaixaun

  /// 壓縮和解壓文件 

  /// </summary> 

  public class ZipClass

  {

    /// <summary> 

    /// 所有文件緩存 

    /// </summary> 

    List<string> files = new List<string>();

    /// <summary> 

    /// 所有空目錄緩存 

    /// </summary> 

    List<string> paths = new List<string>();

    /// <summary> 

    /// 壓縮單個文件根據(jù)文件地址

    /// </summary> 

    /// <param name="fileToZip">要壓縮的文件</param> 

    /// <param name="zipedFile">壓縮后的文件全名</param> 

    /// <param name="compressionLevel">壓縮程度，范圍0-9，數(shù)值越大，壓縮程序越高</param> 

    /// <param name="blockSize">分塊大小</param> 

    public void ZipFile(string fileToZip, string zipedFile, int compressionLevel, int blockSize)

    {

      if (!System.IO.File.Exists(fileToZip))//如果文件沒有找到，則報錯 

      {

        throw new FileNotFoundException("The specified file " + fileToZip + " could not be found. Zipping aborderd");

      }

      FileStream streamToZip = new FileStream(fileToZip, FileMode.Open, FileAccess.Read);

      FileStream zipFile = File.Create(zipedFile);

      ZipOutputStream zipStream = new ZipOutputStream(zipFile);

      ZipEntry zipEntry = new ZipEntry(fileToZip);

      zipStream.PutNextEntry(zipEntry);

      zipStream.SetLevel(compressionLevel);

      byte[] buffer = new byte[blockSize];

      int 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 (Exception ex)

      {

        GC.Collect();

        throw ex;

      }

      zipStream.Finish();

      zipStream.Close();

      streamToZip.Close();

      GC.Collect();

    }

    /// <summary> 

    /// 壓縮目錄（包括子目錄及所有文件） 

    /// </summary> 

    /// <param name="rootPath">要壓縮的根目錄</param> 

    /// <param name="destinationPath">保存路徑</param> 

    /// <param name="compressLevel">壓縮程度，范圍0-9，數(shù)值越大，壓縮程序越高</param> 

    public void ZipFileFromDirectory(string rootPath, string destinationPath, int compressLevel)

    {

      GetAllDirectories(rootPath);

      /* while (rootPath.LastIndexOf("\\") + 1 == rootPath.Length)//檢查路徑是否以"\"結(jié)尾 

      { 

       rootPath = rootPath.Substring(0, rootPath.Length - 1);//如果是則去掉末尾的"\" 

      } 

      */

      //string rootMark = rootPath.Substring(0, rootPath.LastIndexOf("\\") + 1);//得到當(dāng)前路徑的位置，以備壓縮時將所壓縮內(nèi)容轉(zhuǎn)變成相對路徑。 

      string rootMark = rootPath + "\\";//得到當(dāng)前路徑的位置，以備壓縮時將所壓縮內(nèi)容轉(zhuǎn)變成相對路徑。 

      Crc32 crc = new Crc32();

      ZipOutputStream outPutStream = new ZipOutputStream(File.Create(destinationPath));

      outPutStream.SetLevel(compressLevel); // 0 - store only to 9 - means best compression 

      foreach (string file in files)

      {

        FileStream fileStream = File.OpenRead(file);//打開壓縮文件 

        byte[] buffer = new byte[fileStream.Length];

        fileStream.Read(buffer, 0, buffer.Length);

        ZipEntry entry = new ZipEntry(file.Replace(rootMark, string.Empty));

        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 = fileStream.Length;

        fileStream.Close();

        crc.Reset();

        crc.Update(buffer);

        entry.Crc = crc.Value;

        outPutStream.PutNextEntry(entry);

        outPutStream.Write(buffer, 0, buffer.Length);

      }

   this.files.Clear();

    foreach (string emptyPath in paths)

      {

        ZipEntry entry = new ZipEntry(emptyPath.Replace(rootMark, string.Empty) + "/");

        outPutStream.PutNextEntry(entry);

      }

      this.paths.Clear();

      outPutStream.Finish();

      outPutStream.Close();

      GC.Collect();

    }

    /// <summary> 

    /// 多文件打包下載

    /// </summary> 

    public void DwonloadZip(string[] filePathList, string zipName)

    {

      MemoryStream ms = new MemoryStream();

      byte[] buffer = null;

      var context = HttpContext.Current;

      using (ICSharpCode.SharpZipLib.Zip.ZipFile file = ICSharpCode.SharpZipLib.Zip.ZipFile.Create(ms))

      {

        file.BeginUpdate();

        file.NameTransform = new MyNameTransfom();//通過這個名稱格式化器，可以將里面的文件名進行一些處理。默認情況下，會自動根據(jù)文件的路徑在zip中創(chuàng)建有關(guān)的文件夾。

        foreach (var it in filePathList)

        {

          file.Add(context.Server.MapPath(it));

        }

        file.CommitUpdate();

        buffer = new byte[ms.Length];

        ms.Position = 0;

        ms.Read(buffer, 0, buffer.Length);

      }

      context.Response.AddHeader("content-disposition", "attachment;filename=" + zipName);

      context.Response.BinaryWrite(buffer);

      context.Response.Flush();

      context.Response.End();

    }

    /// <summary> 

    /// 取得目錄下所有文件及文件夾，分別存入files及paths 

    /// </summary> 

    /// <param name="rootPath">根目錄</param> 

    private void GetAllDirectories(string rootPath)

    {

      string[] subPaths = Directory.GetDirectories(rootPath);//得到所有子目錄 

      foreach (string path in subPaths)

      {

        GetAllDirectories(path);//對每一個字目錄做與根目錄相同的操作：即找到子目錄并將當(dāng)前目錄的文件名存入List 

      }

      string[] files = Directory.GetFiles(rootPath);

      foreach (string file in files)

      {

        this.files.Add(file);//將當(dāng)前目錄中的所有文件全名存入文件List 

      }

      if (subPaths.Length == files.Length && files.Length == 0)//如果是空目錄 

      {

        this.paths.Add(rootPath);//記錄空目錄 

      }

    }

    /// <summary> 

    /// 解壓縮文件(壓縮文件中含有子目錄) 

    /// </summary> 

    /// <param name="zipfilepath">待解壓縮的文件路徑</param> 

    /// <param name="unzippath">解壓縮到指定目錄</param> 

    /// <returns>解壓后的文件列表</returns> 

    public List<string> UnZip(string zipfilepath, string unzippath)

    {

      //解壓出來的文件列表 

      List<string> unzipFiles = new List<string>();

      //檢查輸出目錄是否以“\\”結(jié)尾 

      if (unzippath.EndsWith("\\") == false || unzippath.EndsWith(":\\") == false)

      {

        unzippath += "\\";

      }

      ZipInputStream s = new ZipInputStream(File.OpenRead(zipfilepath));

      ZipEntry theEntry;

      while ((theEntry = s.GetNextEntry()) != null)

      {

        string directoryName = Path.GetDirectoryName(unzippath);

        string fileName = Path.GetFileName(theEntry.Name);

        //生成解壓目錄【用戶解壓到硬盤根目錄時，不需要創(chuàng)建】 

        if (!string.IsNullOrEmpty(directoryName))

        {

          Directory.CreateDirectory(directoryName);

        }

        if (fileName != String.Empty)

        {

          //如果文件的壓縮后大小為0那么說明這個文件是空的,因此不需要進行讀出寫入 

          if (theEntry.CompressedSize == 0)

            break;

          //解壓文件到指定的目錄 

          directoryName = Path.GetDirectoryName(unzippath + theEntry.Name);

          //建立下面的目錄和子目錄 

          Directory.CreateDirectory(directoryName);

         //記錄導(dǎo)出的文件 

          unzipFiles.Add(unzippath + theEntry.Name);

         FileStream streamWriter = File.Create(unzippath + 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();

      GC.Collect();

      return unzipFiles;

    }

  }

  public class MyNameTransfom : ICSharpCode.SharpZipLib.Core.INameTransform

  {

    #region INameTransform 成員

    public string TransformDirectory(string name)

    {

      return null;

    }

    public string TransformFile(string name)

    {

      return Path.GetFileName(name);

    }

    #endregion

  }

} 

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