实现asp.net的文件压缩、解压、下载

很早前就想做文件的解压、压缩、下载
了，不过一直没时间，现在项目做完了，今天弄了下。不过解压，压缩的方法还是看的网上的，嘻嘻~~不过我把它们综合了一下哦。呵呵~~
1.先要从网上下载一个icsharpcode.sharpziplib.dll
2.建立类AttachmentUnZip，内容如下：
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using ICSharpCode.SharpZipLib.Zip;
using ICSharpCode.SharpZipLib.GZip;
using ICSharpCode.SharpZipLib.BZip2;
using ICSharpCode.SharpZipLib.Checksums;
using ICSharpCode.SharpZipLib.Zip.Compression;
using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
using System.IO;
/// <summary>
///AttachmentUnZip 的摘要说明
/// </summary>
public class AttachmentUnZip
{
    public AttachmentUnZip()
    {
        //
        //TODO: 在此处添加构造函数逻辑
        //
    }
    public static void UpZip(string zipFile)
    {
        string[] FileProperties = new string[2];
        FileProperties[0] = zipFile;//待解压的文件
        FileProperties[1] = zipFile.Substring(0, zipFile.LastIndexOf("\\") + 1);//解压后放置的目标目录
        UnZipClass UnZc = new UnZipClass();
        UnZc.UnZip(FileProperties);
    }
}
3.建立类UnZipClass，内容如下：
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.IO;
using IC