.net - Tagging individual pages of a PDF with ItextSharp C# -

i working itextsharp 5.5.6.0

my goal add key each page , have persistent when read document again application. want able keep track of every page individually (the key unique, , comes source).

this import/write code:

 using (pdfreader reader = new pdfreader(sourcepdfpath))  {          using (document document = new document(reader.getpagesizewithrotation(pagenumber)))         {              pdfcopy pdfcopyprovider = new pdfcopy(document, new system.io.filestream(outputpdfpath, system.io.filemode.create));             pdfcopyprovider.settagged();             pdfcopyprovider.pdfversion = pdfwriter.version_1_7;              pdfimportedpage importedpage = pdfcopyprovider.getimportedpage(reader, pagenumber, true);             importedpage.setaccessibleattribute(pdfname.alt, new pdfstring("mykey"));             pdfcopyprovider.addpage(importedpage);                        }  } 

this read code:

using (memorystream ms = new memorystream())         {             document document = new document();             pdfcopy copy = new pdfcopy(document, ms);             copy.settagged();             document.open();             (int = 0; < pdfs.count; ++i)             {                 var pdf = file.readallbytes(pdfs[i]);                 pdfreader reader = new pdfreader(pdf);                 int n = reader.numberofpages;                 (int page = 0; page < n; )                 {                     var importpage = copy.getimportedpage(reader, ++page, true);                     var mykey = importpage.getaccessibleattribute(pdfname.alt);                     if (mykey != null)                         //do key                     copy.addpage(importpage);                 }             }             document.close();             copy.close();               return ms.toarray();         } 

i trying add accessibility alt text. currently, use attribute on images, , applications set leave attributes untouched.

the problem when add attribute way, save pdf file, , read on process, attribute no longer there.

i open other options, resolve problem of having primary key per page, can assign, read , remove

i trying avoid adding hidden field on each page.

i have little experience itext programming or c# i'm ideal answer question :)

first of all, if want mark page , afterwards find again, please do not use accessibility features in pdf. accessibility there assistive devices, abusing features isn't nice.

especially because - if understand correctly want - there no need so. if want mark page, should page dictionary, example:

pdfreader reader = new itextsharp.text.pdf.pdfreader(file_content); pdfdictionary pagedict = reader.getpagen(i); 

copied from: http://goobbe.com/questions/8099416/how-to-get-the-userunit-property-from-a-pdffile-using-itextsharp-pdfreader

once have dict, can insert own private key in there:

public void put(pdfname key, pdfobject object); 

the value assign you, if want follow rules, have use second class pdf name key. key consists of developer prefix - should registered unique , private part. example key like:

ficl:pagenumber 

in case "ficl" developer prefix , "pagenumber" identification of data adding.

to register developer prefix, see adobe web site, example here: http://www.adobe.com/content/dam/adobe/en/devnet/acrobat/pdfs/pdfregistry_v3.pdf

hope helps.

ps: if here knows owns "ficl" prefix , letters come from, i'll buy beer :)