Create and stream image archive zip file for download C#

Question

I am using the beloved DotNetZip archiving library in MVC3 to generate a Zip file on the fly which contains .png images from binaries stored in a database. I then stream the gen

Answer 1

Your calls to stream.Seek(0, SeekOrigin.Begin) are causing the contents of the stream to be overwritten each iteration with the most recent image data. Try this instead:

using (ZipFile zipFile = new ZipFile())
{
    foreach (var userPicture in userPictures)
    {
        string pictureName = userPicture.Name + ".png";
        using (MemoryStream tempstream = new MemoryStream())
        {
            Image userImage = //method that returns Drawing.Image from byte[];   
            userImage.Save(tempstream, ImageFormat.Png);  
            tempstream.Seek(0, SeekOrigin.Begin);
            byte[] imageData = new byte[tempstream.Length];
            tempstream.Read(imageData, 0, imageData.Length);
            zipFile.AddEntry(pictureName, imageData);
        }
    }

    zipFile.Save(Response.OutputStream);
}