I need get a list of all files in device (phone or PC) in my universal app. In wpf I did somesing like that:

```
class Collection {
    private StringCollection seachResults; 
    //find all mp3 files in local storage
    private void ScanDrives() {
        seachResults.Clear();
        string[] drives = Environment.GetLogicalDrives();
        foreach (string dr in drives) {
            DriveInfo di = new DriveInfo(dr);
            if (!di.IsReady) {
                //skip if drive not ready
                continue;
            }
            DirectoryInfo rootDir = di.RootDirectory;
            WalkDirectoryTree(rootDir);
        }
    }

    private void WalkDirectoryTree(DirectoryInfo root) {
        FileInfo[] files = null;
        DirectoryInfo[] subDirs = null;
        try {
            files = root.GetFiles("*.mp3");
        } catch (UnauthorizedAccessException e) {

        } catch (DirectoryNotFoundException e) {

        }

        if (files != null) {
            foreach (FileInfo fileInfo in files) {
                seachResults.Add(fileInfo.FullName);
            }
            subDirs = root.GetDirectories();
            foreach (DirectoryInfo dirInfo in subDirs) {
                WalkDirectoryTree(dirInfo);
            }
        }
    }
}

```

But when I try to migrate this into winRT app I get a few errors like `unknown type Drive` and `unexisted method Environment.GetLogicalDrives()`. 

Can anyone say how do that in winRT?