Pragmatically download files to zip

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Here's what I have in the button click event.

C#

SqlConnection con = new SqlConnection(main.ConnString);
            SqlCommand cmd1 = new SqlCommand();

            cmd1.CommandText = selectstatement;

            cmd1.Connection = con;

            con.Open();

            SqlDataReader r1 = cmd1.ExecuteReader();
            MemoryStream mem = new MemoryStream();
            ZipArchive zip = new ZipArchive(mem, ZipArchiveMode.Update, false);

            foreach (var item in r1)
            {
                //MemoryStream mem2 = new MemoryStream();
                //mem2.CopyTo(zip.CreateEntry(r1["filename"].ToString().Trim()).Open());

                var zipEntry = zip.CreateEntry((string)r1["filename"]);

                //Get the stream of the attachment
                using (var originalFileStream = new MemoryStream((byte[])r1["stored_content"]))
                {
                    using (var zipEntryStream = zipEntry.Open())
                    {
                        //Copy the attachment stream to the zip entry stream
                        originalFileStream.CopyTo(zipEntryStream);
                    }
                }

            }

            sendOutZIP(mem.ToArray(), "FileName.zip");

Here's what the sendOutZIP looks like

C#

private void sendOutZIP(byte[] zippedFiles, string filename)
        {
            Response.Clear();
            Response.ClearContent();
            Response.ClearHeaders();
            Response.ContentType = "application/x-compressed";
            Response.Charset = string.Empty;
            Response.Cache.SetCacheability(HttpCacheability.Public);
            Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);
            Response.BinaryWrite(zippedFiles);
            Response.OutputStream.Flush();
            Response.OutputStream.Close();
            Response.End();
        }

What I have tried:

The database has contents and when I download it one by one it works.. But when i execute this code it downloads a zip file yea. But it says the zip file is corrupt. What did I do wrong here>

Posted 13-Apr-21 18:25pm

xRomir de La Torre

Updated 13-Apr-21 19:21pm

v2

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[no name] 14-Apr-21 0:32am

Start by comparing lengths.

1 solution

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xRomir de La Torre · Accepted Answer · 2021-04-13T19:21:00

just changed the above code like as follows and it worked!

C#

SqlConnection con = new SqlConnection(main.ConnString);
            SqlCommand cmd1 = new SqlCommand();

            cmd1.CommandText = selectstatement;

            cmd1.Connection = con;

            con.Open();

            SqlDataReader r1 = cmd1.ExecuteReader();
            using (var compressedFileStream = new MemoryStream())
            {
                //Create an archive and store the stream in memory.
                using (var zipArchive = new ZipArchive(compressedFileStream, ZipArchiveMode.Create, false))
                {
                    foreach (var caseAttachmentModel in r1)
                    {
                        //Create a zip entry for each attachment
                        var zipEntry = zipArchive.CreateEntry((string)r1["filename"]);

                        //Get the stream of the attachment
                        using (var originalFileStream = new MemoryStream((byte[])r1["stored_content"]))
                        using (var zipEntryStream = zipEntry.Open())
                        {
                            //Copy the attachment stream to the zip entry stream
                            originalFileStream.CopyTo(zipEntryStream);
                        }
                    }
                }
                sendOutZIP(compressedFileStream.ToArray(), "FileName.zip");
            }