public async Task searchDir(int id)
{
List <FileSystemObject> fsoList = await _context.FileSystemObjects.ToListAsync();
IEnumerable <FileSystemObject> subDirList = new List <FileSystemObject>();
subDirList = from dir in fsoList
where dir.ParentId == id
select dir;
foreach (var f in subDirList)
{
SearchScope.Add(f);
if (f.IsFolder)
{
await searchDir(f.Id);
}
}
}