c# - Zebra won't print when I write filestream -

i trying print raw zpl data zebra printer using byte array. when run program nothing prints , program passes through no issue. time print asking if step through , check filestream values before close it, label print. can causing this?

update: made suggested adjustments code , winapp.

 public bool labelprinting(datatable dt, string lblpath)     {         if (file.exists(lblpath))         {             string strcontent = "";             string comport = cboport.text.trim();             streamreader myfile = new streamreader(lblpath);              strcontent = myfile.readtoend();             myfile.close();               if (strcontent.length == 0)             {                 return false;             }             else             {                 char[] bigspacechars = { convert.tochar(0x09) };                 strcontent = strcontent.replace(new string(bigspacechars), "   ");                 strcontent = strcontent.replace("<cpn>", dt.rows[0]["cpn"].tostring().toupper());                 strcontent = strcontent.replace("<rackasset>", dt.rows[0]["rackasset"].tostring().toupper());                 strcontent = strcontent.replace("<loc>", dt.rows[0]["loc"].tostring().toupper());                  byte[] buffer = new byte[strcontent.length];                 buffer = system.text.encoding.ascii.getbytes(strcontent);                  safefilehandle printer = createfile(comport,fileaccess.readwrite,0,intptr.zero,filemode.open,0,intptr.zero);                  if (printer.isinvalid == true)                 {                     return false;                 }                     using (filestream com = new filestream(printer, fileaccess.readwrite))                     {                         com.write(buffer, 0, buffer.length);                         com.flush();                         com.close();                     }                   }                 return true;             }