c# - What need I do to get this code to work in a Portable Class Library? -

i'm wondering if portable class library more restricted in functionality compact framework.

i'm trying port cf/windows ce app (runs on handheld device) xamarin solution target android, ios, windows phone, , perhaps other things.

one of problems run into, though, legacy code (which works under cf):

public static list<string> getxmlfiles(string filetype, string startingdir) {     const string extension = ".xml";     string dirname = startingdir;     // call so: getxmlfiles("abc", "\\");  <= think double-whack need windows ce device...am right?     var filenames = new list<string>();     try     {         foreach (string f in directory.getfiles(dirname))         {             string extension = path.getextension(f);             if (extension != null)             {                 string ext = extension.toupper();                 string filenameonly = path.getfilenamewithoutextension(f);                 if (filenameonly != null &&                     ((ext.equals(extension, stringcomparison.ordinalignorecase)) &&                      (filenameonly.contains(filetype))))                 {                     filenames.add(f);                 }             }         }         foreach (string d in directory.getdirectories(dirname))         {             filenames.addrange(getxmlfiles(filetype, d));                 // brad rem's answer here: http://stackoverflow.com/questions/22186198/why-is-this-function-returning-nothing-although-there-is-a-match/22186351?noredirect=1#22186351         }     }     catch (exception ex)     {         messagebox.show(ex.message);     }     return filenames; } 

...won't compile in xamarin/cpl solution. get, "the name 'directory' not exist in current context" , right-clicking word not afford "resolve" option.

is there way pcl recognize "directory" or must rewrite code? if latter, have suggestions on do/use in stead?

relatedly, there url show me [not] available in pcl and/or site show how of provided block of code "pcl-ready"?

update

the first image in this article illuminating. later on, talks "directory" not being available in pcl scenario.

update 2

i downloaded pclstorage package referenced daniel plaisted below allow me access file system within pcl project.

using sample code @ start of download page [http://pclstorage.codeplex.com/] starting point, i've gotten far:

public async task<list<string>> getxmlfiles(string filetype, string startingdir) {     const string extension = ".xml";      ifolder rootfolder = filesystem.current.localstorage;     ifolder folder = await rootfolder.getfolderasync(startingdir, creationcollisionoption.openifexists); //createfolderasync(startingdir, creationcollisionoption.openifexists);     list<string> filenames = await folder.getfilesasync(extension);     return filenames; } 

...but "extension" arg getfilesasync() not right. this, "argument 1: cannot convert 'string' 'system.threading.cancellationtoken'"

so need *.xml files folder?

update 3

this compiles, i'm not @ sure it's right way it, besides fact gets all files folder, rather match "*.xml":

public async task<list<ifile>> getxmlfiles(string filetype, string startingdir) {     const string extension = ".xml";      ifolder rootfolder = filesystem.current.localstorage;     ifolder folder = await rootfolder.getfolderasync(startingdir, system.threading.cancellationtoken.none);     ilist<pclstorage.ifile> filenames = await folder.getfilesasync(system.threading.cancellationtoken.none);      return filenames.tolist(); } 

windows phone applications not use file system of operating system , restricted using isolated storage persist , access files, namespace not provide additional functionality.

http://msdn.microsoft.com/en-us/library/windowsphone/develop/system.io%28v=vs.105%29.aspx