itextsharp - asp itext with vb.net stream -

i have problems fill pdf file, when try open file damaged.

imports itextsharp.text imports itextsharp.text.pdf imports itextsharp.text.pdf.parser imports system.data imports system.io  public sub fillpdf()     dim mspdf new memorystream     dim reader new pdfreader(request.mappath("~/pdffiles/form01.pdf"))       dim workinfolder = environment.getfolderpath(environment.specialfolder.recent)     dim workinfile = path.combine(workinfolder, "pres-19072013.pdf")      dim formfiller new pdfstamper(reader, mspdf)      dim formfields acrofields     formfields = formfiller.acrofields      formfields.setfield("order", "01999")     formfields.setfield("datepdf", "17/07/2013")      response.clear()     response.addheader("content-type", "application/pdf")     response.addheader("cache-control", "no-cache")     response.addheader("accept-ranges", "none")     response.addheader("content-disposition", "attachment; filename=pres2013.pdf")      mspdf.writeto(response.outputstream)      response.flush()     response.end()  end sub 

previously using filestream, generated either files, need have memorystream website

the pdf corrupt because forgot close pdfstamper instance. use close'() method right after sequence of setfield() operations.