How can I update an element of an existing XML file in c# Windows 8 App? -

i have xml file located in assets folder. face no problem when tried read file using linq. however, when wanted write file see no error , target element never gets updated.

my codes below:

private static readonly string mealsxmlpath = path.combine(package.current.installedlocation.path, "assets/meals.xml");     private xdocument loadeddata; 

in constructor have initialisation code:

loadeddata = xdocument.load(mealsxmlpath); 

the actual code using update existing element value here

public async void updatequantity(dictionary<int, int> orderdetails)         {             xdocument xmlfile = xdocument.load(mealsxmlpath);             foreach(var key in orderdetails.keys)             {                 xelement upd = (from order in xmlfile.descendants("meal")                                 order.element("id").value == key.tostring()                                 select order).single();                 upd.element("avaibility").value = (convert.toint32(upd.element("avaibility").value) - orderdetails[key]).tostring();               }         } 

i have tried other built in methods such xdoc.save("path") , xml...create(..).but none seems working in c# windows 8 app.

you have save document writable directory :

using (var stream = await (await applicationdata.current.localfolder.createfileasync(system.io.path.getfilename(mealsxmlpath))).openasync(fileaccessmode.readwrite)) {     xmlfile.save(stream.asstreamforwrite()); }