c# - Error when trying to write then read a XML file in Windows Phone 8 app -

edited : adding informations gathered since posted this.

hi stackers ! i'm trying first time metro style windows phone 8 app using visual studio 2013 , wp8 sdk.

this app should able store few data users in xml files stored in app folder.

here should :

the user use app normal way, , saves data. want add in datafile.xml file created xml declaration line , root element. then, if user want see saved, app should data in xml file , display it.

here basic xml file:

<?xml version="1.0" encoding="utf-8" ?> <itemlist>  </itemlist> 

and code write data : (modifications edit here)

var isofilestream = new isolatedstoragefilestream("saves\\itemlist.xml", filemode.openorcreate, fileaccess.readwrite, store); //where store definition of isolatedstoragefile var xdoc = xdocument.load(isofilestream);                     var newitem = new xelement("item",                             new xelement("name", itemname.text),                             //all other elements here                             new xelement("method", method));         xdoc.root.add(newitem);         xdoc.root.save(isofilestream);         isofilestream.close(); 

thanks isolatedstorage , isetool.exe, able retrieve xml file after writing inside using code above. here result :

<?xml version="1.0" encoding="utf-8" ?> <itemlist></itemlist><?xml version="1.0" encoding="utf-8"?>     <itemlist>         <item>             <name>my item</name>             <method>item method</method>         </item>     </itemlist> 

so, resume, code loaded xml file shown above, detected root element using xdoc.root, , added item inside it. but, when saving, recreates xml declaration , root element, making file structure incorrect, unusable. why ? question. how fix ? that's love know.

any idea ?

thanks lot in advance :)

i found how deal this, i'm answering own question, in case have same problem.

the problem here :

xdoc.root.save(isofilestream); 

this saves xdocument formatted in code using file stream used load previous content of xml file. xdocument.save function made format xml file usable if file empty. so, writes data @ end of file, making structure incorrect adding 2 declarations.

the solution gather xml content in var xdoc using xdocument.load(filestream), close stream , open new 1 filemode option set create, overwrite existing file :

var isofilestream = new isolatedstoragefilestream("saves\\itemlist.xml", filemode.openorcreate, fileaccess.readwrite, store); var xdoc = xdocument.load(isofilestream); isofilestream.close(); isofilestream = new isolatedstoragefilestream("saves\\itemlist.xml", filemode.create, fileaccess.readwrite, store);                     var newitem = new xelement("item",                             new xelement("name", itemname.text),                             //all other elements here                             new xelement("method", method));         xdoc.root.add(newitem);         xdoc.save(isofilestream);         isofilestream.close(); 

this working using this. ones answered :)