c# 壓縮與解壓的簡單學習

         System.IO.Compression命名空間包含能壓縮代碼中文件的類，這些類使用GZIP或Deflate算法，這兩種算法都是公開的、免費的。
         System.IO.Compression命名空單中有兩個奪縮流類DeflateStream和GZipStream。
以GZipStream為例，用代碼來學習。

using  System.IO.Compression;
using  System.IO;

namespace  MyZip
{
     public   partial   class  Form1 : Form
    {
         public  Form1()
        {
            InitializeComponent();

            btnCompressed.Click  +=   new  EventHandler(btnCompressed_Click);
            btnUnCompressed.Click  +=   new  EventHandler(btnUnCompressed_Click);
        }

         ///   <summary>
         ///  壓縮文件
         ///   </summary>
         ///   <param name="asSouceFile"> 被壓縮的文件的完整路徑 </param>
         ///   <param name="asZipFileName"> 被解壓文件的完整路徑 </param>
         private   void  SaveCompressdFile( string  asSouceFile,  string  asZipFileName)
        {
             string  sData  =  ReadFile(asSouceFile);
            FileStream fsStream  =   new  FileStream(asZipFileName, FileMode.Create, FileAccess.Write);
             // 壓縮
            GZipStream gzStream  =   new  GZipStream(fsStream, CompressionMode.Compress);
            StreamWriter swWriter  =   new  StreamWriter(gzStream);
            swWriter.Write(sData);
            swWriter.Close();
        }

         ///   <summary>
         ///  解壓文件
         ///   </summary>
         ///   <param name="asZipFileName"> 被解壓文件的完整路徑 </param>
         ///   <param name="asUnZipFileName"> 解壓後文件的完整路徑 </param>
         private   void  LoadCompressdFile( string  asZipFileName, string  asUnZipFileName)
        {
            FileStream fsStream  =   new  FileStream(asZipFileName, FileMode.Open, FileAccess.Read);
             // 解壓縮
            GZipStream gzStream  =   new  GZipStream(fsStream, CompressionMode.Decompress);
            StreamReader srReader  =   new  StreamReader(gzStream);
             string  sData =  srReader.ReadToEnd();
            srReader.Close();
            WriteFile(asUnZipFileName, sData);
        }

         ///   <summary>
         ///  讀取文件
         ///   </summary>
         ///   <param name="asSouceFile"> 被讀取文件的完整路徑 </param>
         ///   <returns></returns>
         private   string  ReadFile( string  asSouceFileName)
        {
             string  sValue = "" ;
             try
            {
                FileStream fsStream  =   new  FileStream(asSouceFileName, FileMode.Open, FileAccess.Read);
                StreamReader srReader  =   new  StreamReader(asSouceFileName);
                sValue  =  srReader.ReadToEnd();
                srReader.Close();
            }
             catch  (Exception ex)
            {
                 throw  ex;
            }
             return  sValue;
        }

     
         ///   <summary>
         ///  寫入文件
         ///   </summary>
         ///   <param name="asFileName"> 寫入後文件的完整路徑 </param>
         ///   <param name="asData"> 被寫入的資料 </param>
         ///   <returns></returns>
         private   void  WriteFile( string  asFileName, string  asData)
        {
            FileStream fsStream  =   new  FileStream(asFileName, FileMode.OpenOrCreate, FileAccess.Write);
            StreamWriter swWriter  =   new  StreamWriter(fsStream);
            swWriter.Write(asData);
            swWriter.Close();
        }
         ///   <summary>
         ///  壓縮按鈕事件的方法
         ///   </summary>
         ///   <param name="sender"></param>
         ///   <param name="e"></param>
         void  btnCompressed_Click( object  sender, EventArgs e)
        {
            SaveCompressdFile( @" D:\log.txt " ,  @" D:\zip.txt " );
        }

         ///   <summary>
         ///  解壓縮壓按鈕事件的方法
         ///   </summary>
         ///   <param name="sender"></param>
         ///   <param name="e"></param>
         void  btnUnCompressed_Click( object  sender, EventArgs e)
        {
            LoadCompressdFile( @" D:\zip.txt " ,  @" D:\unzip.txt " );
        }

    }
}