打包下载，byte[] ，

1.多byte[] 打包下载

var streamsDict = new Dictionary<string, byte[]>();
// 循环添加到 streamsDict
var ds=new DataSet();
streamsDict.Add(ds.DataSetName+ ".xls", NPOIHelper.ExportDataSet(ds).GetBuffer());

HttpContext curContext = HttpContext.Current;
MemoryStream ms = new MemoryStream();
ms = DownLoadHelper.PackageZip(streamsDict);
byte[] bytes = new byte[(int)ms.Length];
ms.Read(bytes, 0, bytes.Length);
ms.Close();
curContext.Response.ContentType = "application/octet-stream";
curContext.Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode($"数据下载{DateTime.Now:yyyyMMddHHmmss}.zip", System.Text.Encoding.UTF8));
curContext.Response.BinaryWrite(bytes);
curContext.Response.Flush();

2.多文件打包下载

// existPathlist list，文件路径
if (existPathlist.Any())
    {
        var buffer = DownLoadHelper.Download(existPathlist, $"评级信息{DateTime.Now:yyyyMMddHHmmss}.zip");
        Response.AddHeader("content-disposition", "attachment;filename=" + $"评级信息{DateTime.Now:yyyyMMddHHmmss}.zip");
        Response.BinaryWrite(buffer);
        Response.Flush();
        Response.End();
    }

public static class DownLoadHelper
{
    public static byte[] Download(IEnumerable<string> files, string zipFileName)
    {
        //根据所选文件打包下载
        MemoryStream ms = new MemoryStream();
        byte[] buffer = null;

        using (ZipFile file = ZipFile.Create(ms))
        {
            file.BeginUpdate();
            file.NameTransform = new MyNameTransfom();//通过这个名称格式化器，可以将里面的文件名进行一些处理。默认情况下，会自动根据文件的路径在zip中创建有关的文件夹。

            foreach (var item in files)
            {
                file.Add(item);
            }
            file.CommitUpdate();
            buffer = new byte[ms.Length];
            ms.Position = 0;
            ms.Read(buffer, 0, buffer.Length);
        }

        return buffer;
    }

    /// <summary>
    /// 将多个流进行zip压缩，返回压缩后的流
    /// </summary>
    /// <param name="streams">key：文件名；value：文件名对应的要压缩的流</param>
    /// <returns>压缩后的流</returns>
    public static MemoryStream PackageZip(Dictionary<string, Stream> streams)
    {
        byte[] buffer = new byte[6500];
        MemoryStream returnStream = new MemoryStream();
        var zipMs = new MemoryStream();
        using (ZipOutputStream zipStream = new ZipOutputStream(zipMs))
        {
            zipStream.SetLevel(9);
            foreach (var kv in streams)
            {
                string fileName = kv.Key;
                using (var streamInput = kv.Value)
                {
                    zipStream.PutNextEntry(new ZipEntry(fileName));
                    while (true)
                    {
                        var readCount = streamInput.Read(buffer, 0, buffer.Length);
                        if (readCount > 0)
                        {
                            zipStream.Write(buffer, 0, readCount);
                        }
                        else
                        {
                            break;
                        }
                    }
                    zipStream.Flush();
                }
            }
            zipStream.Finish();
            zipMs.Position = 0;
            zipMs.CopyTo(returnStream, 5600);
        }
        returnStream.Position = 0;
        return returnStream;
    }

    /// <summary>
    /// 将多个byte[]进行zip压缩，返回压缩后的流
    /// </summary>
    /// <param name="streams">key：文件名；value：文件名对应的byte</param>
    /// <returns>压缩后的流</returns>
    public static MemoryStream PackageZip(Dictionary<string, byte[]> streams)
    {
        MemoryStream returnStream = new MemoryStream();
        var zipMs = new MemoryStream();
        using (ZipOutputStream zipStream = new ZipOutputStream(zipMs))
        {
            zipStream.SetLevel(9);
            foreach (var kv in streams)
            {
                string fileName = kv.Key;
                var streamInput = kv.Value;
                zipStream.PutNextEntry(new ZipEntry(fileName));
                zipStream.Write(streamInput, 0, streamInput.Length);
                zipStream.Flush();
            }
            zipStream.Finish();
            zipMs.Position = 0;
            zipMs.CopyTo(returnStream, 5600);
        }
        returnStream.Position = 0;
        return returnStream;
    }
}



public class MyNameTransfom : ICSharpCode.SharpZipLib.Core.INameTransform
{
    #region INameTransform 成员
    public string TransformDirectory(string name)
    {
        return null;
    }
    public string TransformFile(string name)
    {
        return Path.GetFileName(name);
    }

    #endregion
}