c# - Remove Document variables for OpenXML DOCX? -

i'm trying remove doc variables docx file. here code i'm using, doesn't remove any...

this complete code:

class program     {         static void main(string[] args)         {             string filepath = "c:\\..\\..sample.docx";             remove removedocvars = new remove();             removedocvars.removedocvariables(filepath);          }     }  //method remove doc vars   public void removedocvariables(string filename)         {             using (wordprocessingdocument doc = wordprocessingdocument.open(filename, true))             {                  list<documentvariables> docvarstodelete = doc.maindocumentpart.rootelement.descendants<documentvariables>().tolist();                 foreach (documentvariables dc in docvarstodelete)                 {                     dc.remove();                 }                 doc.maindocumentpart.document.save();             }         } 

the variables in settings.xml file, have use maindocumentpart.documentsettingspart.settings.descendants<>().

public void removedocvariables(string filename) {     using (var doc = wordprocessingdocument.open(filename, true))     {         doc.maindocumentpart.documentsettingspart.settings.removeallchildren<documentvariables>();     } }