download multiple files as zip in .net

Question

I have a program which needs to download multiple files at once. I can download a single file by using this single file download, but it doesn't work for multiple.

How can one download multiple files at once in such as as zip file?

Answer 1

You need to pack files and write a result to a response. You can use SharpZipLib compression library.

Code example:

Response.AddHeader("Content-Disposition", "attachment; filename=" + compressedFileName + ".zip");
Response.ContentType = "application/zip";

using (var zipStream = new ZipOutputStream(Response.OutputStream))
{
    foreach (string filePath in filePaths)
    {
        byte[] fileBytes = System.IO.File.ReadAllBytes(filePath);

        var fileEntry = new ZipEntry(Path.GetFileName(filePath))
        {
            Size = fileBytes.Length
        };

        zipStream.PutNextEntry(fileEntry);
        zipStream.Write(fileBytes, 0, fileBytes.Length);
    }

    zipStream.Flush();
    zipStream.Close();
}

Answer 2

This is how to do it the DotNetZip way :D I vouch for DotNetZip because I have used it and it is by far the easiest compression library for C# I've come across :)

Check http://dotnetzip.codeplex.com/

http://dotnetzip.codeplex.com/wikipage?title=CS-Examples&referringTitle=Examples

Create a downloadable zip within ASP.NET. This example creates a zip dynamically within an ASP.NET postback method, then downloads that zipfile to the requesting browser through Response.OutputStream. No zip archive is ever created on disk.

public void btnGo_Click (Object sender, EventArgs e)
{
  Response.Clear();
  Response.BufferOutput= false;  // for large files
  String ReadmeText= "This is a zip file dynamically generated at " + System.DateTime.Now.ToString("G");
  string filename = System.IO.Path.GetFileName(ListOfFiles.SelectedItem.Text) + ".zip";
  Response.ContentType = "application/zip";
  Response.AddHeader("content-disposition", "filename=" + filename);

  using (ZipFile zip = new ZipFile()) 
  {
    zip.AddFile(ListOfFiles.SelectedItem.Text, "files");
    zip.AddEntry("Readme.txt", "", ReadmeText);
    zip.Save(Response.OutputStream);
  }
  Response.Close();
}

Answer 3

Create a ZIP file on the fly using http://www.icsharpcode.net/opensource/sharpziplib/.

Answer 4

The 3 libraries I know of are SharpZipLib (versatile formats), DotNetZip (everything ZIP), and ZipStorer (small and compact). No links, but they are all on codeplex and found via google. The licenses and exact features vary.

Happy coding.

Answer 5

var memoryStream = new MemoryStream();

using (var zipArchive = new ZipArchive(memoryStream, ZipArchiveMode.Create, false))

{
    // Files means your file
    foreach (var file in files)

    {

        var file = _converter.Convert(pdf);

        var entry = zipArchive.CreateEntry($"{await GetUserName(userId)}.pdf");

        using (Stream str = entry.Open())

        {

            str.Write(file);

        }

    }

}

var outdate = memoryStream.ToArray();

return File(outdate, "application/zip", "Trainingcard.zip");