我想使用 SharpZipLib 生成 zip 文件，并让客户端下载它。
目前 zip 文件夹已经创建，在客户端计算机上可用，但问题是 download.zip 文件夹是空白。在 zip 文件夹的某一个文件夹中指定的文件不可用。

下面是我试过的代码。 下面是我试过的代码。
System.Web.HttpResponse response = System.Web.HttpContext.Current.Response;
ICSharpCode.SharpZipLib.Checksums.Crc32 crc = new ICSharpCode.SharpZipLib.Checksums.Crc32();
//stream directly to client. this article is published by codebye.com
ICSharpCode.SharpZipLib.Zip.ZipOutputStream output = new ICSharpCode.SharpZipLib.Zip.ZipOutputStream(response.OutputStream);
output.SetLevel(9);
string[] files =    Directory.GetFiles(“D:/newfolder/”);
for (int i = 0; i < files.Length; i++)
{
    ICSharpCode.SharpZipLib.Zip.ZipEntry entry = new ICSharpCode.SharpZipLib.Zip.ZipEntry(files[i].ToString());
    entry.DateTime = DateTime.Now;
    System.IO.FileStream fs = new System.IO.FileStream(files[i].ToString(), FileMode.Open);     
    byte[] buffer = new byte[fs.Length];
    fs.Read(buffer, 0, buffer.Length);
    entry.Size = fs.Length;
    fs.Close();
    crc.Reset();
    crc.Update(buffer);
    entry.Crc = crc.Value;
    output.PutNextEntry(entry);
    output.Write(buffer, 0, buffer.Length);
}
output.Finish();
output.Close();
response.Clear();
response.ContentType = “D:/Work Area/”;
response.AddHeader(“Content-Disposition”, “attachment; filename=” + “download.zip“);
response.End();
有人能告诉我这是什么原因吗？为什么文件在.zip 中不可用？

方案一：
浏览 SharpDevelop  wiki 后，我发现下面方法也许能帮助你解决问题：
 
using ICSharpCode.SharpZipLib.Zip;
// This will accumulate each of the files named in the fileList into a zip file,
// and stream it to the browser.
// This approach writes directly to the Response OutputStream.
// The browser starts to receive data immediately which should avoid timeout problems.
// This also avoids an intermediate memorystream, saving memory on large files.
//这个方法直接写入 Response 的 OutputStream 。浏览器立即开始接收数据，避免超时问题。这同时节省大文件的内存。
private void DownloadZipToBrowser(List <string> zipFileList)
{
    Response.ContentType = “application/zip”;
    // If the browser is receiving a mangled zipfile, IIS Compression may cause this problem. Some members have found that
    //    Response.ContentType = “application/octet-stream”     has solved this. May be specific to Internet Explorer.
    Response.AppendHeader(“content-disposition”, “attachment; filename=”Download.zip””);
    response.CacheControl = “Private”;
    response.Cache.SetExpires(DateTime.Now.AddMinutes(3)); // or put a timestamp in the filename in the content-disposition
    byte[] buffer = new byte[4096];
    ZipOutputStream zipOutputStream = new ZipOutputStream(Response.OutputStream);
    zipOutputStream.SetLevel(3); //0-9, 9 being the highest level of compression
    foreach (string fileName in zipFileList) {
        Stream fs = File.OpenRead(fileName);    // or any suitable inputstream
        ZipEntry entry = new ZipEntry(ZipEntry.CleanName(fileName));
        entry.Size = fs.Length;
        // Setting the Size provides WinXP built-in extractor compatibility,
        //  but if not available, you can set zipOutputStream.UseZip64 = UseZip64.Off instead.
        zipOutputStream.PutNextEntry(entry);
        int count = fs.Read(buffer, 0, buffer.Length);
        while (count > 0) {
            zipOutputStream.Write(buffer, 0, count);
            count = fs.Read(buffer, 0, buffer.Length);
            if (!Response.IsClientConnected) {
                break;
            }
            Response.Flush();
        }
        fs.Close();
    }
    zipOutputStream.Close();
    Response.Flush();
    Response.End();
}