hello everyone

i have a series of PDF byte arrays in a arraylist files that i wish to concatenate into one file, currently when the PDF application trys to open the file is it corrupted:

       foreach (byte[] array in files)
        {

            using (Stream s = new MemoryStream(downloadbytes))
            {

                    s.Write(array, 0, array.Length);

            }



        }

downloadbytes is the resultant concatenated array of bytes below is another implementation which also failed

      foreach (byte[] array in files)
        {


            System.Buffer.BlockCopy(array, 0, downloadbytes, offset, array.Length);

            offset += array.Length;



        }

any pointers?