c# - overwrite file in Zipping -

i try zip .pdf files in c#. code works fine when size of 1 of pdfs big, going overwrite pdf on rest of pdfs. not sure happening. tried increase size of buffer or zip file still same issue. have suggestion?

this code:

    public void processziprequest(string strqueueid, string strbatchid, string strftppath)     {          int intreportcnt = 0;          string strzipfilename = "order-" + strbatchid + "-" + strqueueid + "-" + datetime.now.tostring("mm-dd-yyyy-hh-mm") + ".zip";         strzipfilename = safefilename(strzipfilename);          //memorystream ms = new memorystream();         filestream ms = new filestream(@"c:\surf\nikoo.zip", filemode.create);         zipoutputstream ozipstream = new zipoutputstream(ms); // create zip stream          ozipstream.setlevel(9); // maximum compression          intreportcnt += 1;          string strrptfilename=string.empty;         memorystream outputstream = new memorystream();         if (strqueueid != null)         {                string[] filenames = directory.getfiles(@"c:\uploaded");              // setting report name path given report name              foreach (string filename in filenames)             {                 strrptfilename = filename.substring(filename.lastindexof("\\") + 1);                    filestream fs = file.openread(@"c:\uploaded\" + strrptfilename);                 int buffersize = 2048;                 int readcount;                 byte[] buffer = new byte[buffersize];                 readcount = fs.read(buffer, 0, buffersize);                 while (readcount>0)                 {                     outputstream.write(buffer, 0, readcount);                     readcount = fs.read(buffer, 0, buffersize);                  }                 fs.close();                 outputstream.position = 0;                   zipfile(ref outputstream, strrptfilename, ref ozipstream);              }          }          outputstream.close();         ozipstream.finish();         ozipstream.flush();          ozipstream.isstreamowner = false;  //  false stops close closing underlying stream.         ozipstream.close();                // must finish zipoutputstream before using outputmemstream.          ms.close();      } 

and zipfile method:

   public void zipfile(ref memorystream msfile, string strfilename, ref zipoutputstream ozipstream)     {         zipentry ozipentry = new zipentry(strfilename);         ozipentry.datetime = datetime.now;         ozipentry.size = msfile.length;          ozipstream.putnextentry(ozipentry);          streamutils.copy(msfile, ozipstream, new byte[4096]);           ozipstream.closeentry();     } 

i found issue. have create new memoystream in loop , close @ end of loop.

foreach (string filename in filenames)             {                 strrptfilename = filename.substring(filename.lastindexof("\\") + 1);                  outputstream = new memorystream();                  filestream fs = file.openread(@"c:\uploaded\" + strrptfilename);                  int buffersize = 2048;                 int readcount;                 byte[] buffer = new byte[buffersize];                 readcount = fs.read(buffer, 0, buffersize);                 while (readcount>0)                 {                     outputstream.write(buffer, 0, readcount);                     readcount = fs.read(buffer, 0, buffersize);                  }                 fs.close();                 outputstream.position = 0;                   zipfile(ref outputstream, strrptfilename, ref ozipstream);                 fs.close();                 outputstream.close();              }