c# - iText sharp SimpleTextExtractionStrategy(); -

i using itextsharp travers through pdf file. not find text imbedded within table.

public bool readpdffilespecial(string filename ) {    var found = false;    if (file.exists(filename))   {     pdfreader pdfreader = new pdfreader(filename);      (int page = 1; page <= pdfreader.numberofpages; page++)     {       itextextractionstrategy strategy = new simpletextextractionstrategy();        string currentpagetext = pdftextextractor.gettextfrompage(pdfreader, page, strategy);       if (currentpagetext.contains("is on 18 years old. children must less 19 years old qualify medikids.  however, "))         found = true; ;     }     pdfreader.close();   }   return found; }