asp.net - How to update a PDF without creating a new PDF? -

i required replace word in existing pdf acrofield word. using pdfstamper of itextsharp same , working fine. but, in doing required create new pdf , change reflected in existing pdf itself. if setting destination filename same original filename no change being reflected.i new itextsharp , there doing wrong? please help.. providing piece of code using

  private void listfieldnames(string s)     {         try         {             string pdftemplate = @"z:\temp\pdf\passportapplicationform_main_english_v1.0.pdf";             string newfile = @"z:\temp\pdf\passportapplicationform_main_english_v1.0.pdf";             pdfreader pdfreader = new pdfreader(pdftemplate);              (int page = 1; page <= pdfreader.numberofpages; page++)             {                 pdfreader reader = new pdfreader((string)pdftemplate);                 using (pdfstamper stamper = new pdfstamper(reader, new filestream(newfile, filemode.create, fileaccess.readwrite)))                 {                     acrofields form = stamper.acrofields;                     var fieldkeys = form.fields.keys;                     foreach (string fieldkey in fieldkeys)                     {                         //replace address form field custom data                         if (fieldkey.contains("address"))                         {                             form.setfield(fieldkey, s);                         }                         }                     stamper.formflattening = true;                     stamper.close();                  }              }         } 

as documented in book itext in action, can't read file , write simultaneously. think of how word works: can't open word document , write directly it. word creates temporary file, writes changes it, replaces original file , throws away temporary file.

you can too:

• read original file pdfreader,
• create temporary file pdfstamper, , when you're done,
• replace original file temporary file.

or:

• read original file byte[],
• create pdfreader byte[], and
• use path original file pdfstamper.

this second option more dangerous, you'll lose original file if causes exception in pdfstamper.