C# Zip Saving byte[] into zip, converting to stream, sending mail as a mail attachment - proper way to attachment document

Question

So below is the code i'm using. Basically it just loops through an array, adds the files to the zip, then saves the zip to a memory stream and then emails the attachment.

When I look at the item in debug I can see that the zipfile has about 20 megabytes of data. When i receive the attachment it only has about 230 bits of data and there is no content. Any thoughts?

byteCount = byteCount + docs[holder].FileSize;
            if (byteCount > byteLimit)
            {
                //create a new stream and save the stream to the zip file
                System.IO.MemoryStream attachmentstream = new System.IO.MemoryStream();
                zip.Save(attachmentstream);

                //create the attachment and send that attachment to the mail
                Attachment data = new Attachment(attachmentstream, "documentrequest.zip");
                theMailMessage.Attachments.Add(data);

                //send Mail
                SmtpClient theClient = new SmtpClient("mymail");
                theClient.UseDefaultCredentials = false;
                System.Net.NetworkCredential theCredential = new System.Net.NetworkCredential("bytebte", "2323232");
                theClient.Credentials = theCredential;
                theClient.Send(theMailMessage);
                zip = new ZipFile();

                //iterate Document Holder
                holder++;
            }
            else
            {
                //create the stream and add it to the zip file
                //System.IO.MemoryStream stream = new System.IO.MemoryStream(docs[holder].FileData);
                zip.AddEntry("DocId_"+docs[holder].DocumentId+"_"+docs[holder].FileName, docs[holder].FileData);
                holder++;

            }

The issue is here Attachment data = new Attachment(attachmentstream, "documentrequest.zip"); once I look at the attachment it has a size of -1 So whats the proper way to attach this item?

Most likely, your call to `zip.Save` closes the attachment stream, making you lose your data. What Zip library are you using? — Jim Mischel, Jun 24 '14 at 18:48
The most important piece of software here (`zip.`) is not identified. — H H, Jun 24 '14 at 19:22
In addition to Jim's answer (even though you've likely put this issue behind you by now; this is more for other readers), you could simply reset the `Stream`'s position. Like so: http://stackoverflow.com/a/2267750/722393. — InteXX, Mar 02 '15 at 23:50

Jim Mischel · Accepted Answer · 2014-06-24T19:14:20.270

2

I suspect that the call to zip.Save closes the stream after it's written. You'll probably end up having to copy the bytes to an array and then create a new MemoryStream for reading. For example:

//create a new stream and save the stream to the zip file
byte[] streamBytes;
using (var ms = new MemoryStream())
{
    zip.Save(ms);
    // copy the bytes
    streamBytes = ms.ToArray();
}

// create a stream for the attachment
using (var attachmentStream = new MemoryStream(streamBytes))
{
    //create the attachment and send that attachment to the mail
    Attachment data = new Attachment(attachmentstream, "documentrequest.zip");
    theMailMessage.Attachments.Add(data);

    // rest of your code here
}

edited Jun 24 '14 at 19:14

answered Jun 24 '14 at 19:01

Jim Mischel

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Jim I can see that on the line Attachment data = new Attachment(attachmentstream, "documentrequest.zip"); the attachmentstream is still the correct size but the attachment has a size of -1 – Jun 24 '14 at 19:02
Jim - your recommendation actually closes the stream and then the mail cannot be sent – Jun 24 '14 at 19:04
ignore my above comment about closed stream, but yeah still an invalid file – Jun 24 '14 at 19:05

C# Zip Saving byte[] into zip, converting to stream, sending mail as a mail attachment - proper way to attachment document

1 Answers1