Untitled

Passing a field to a function to sort on that field
public MyModel GetModel(IQueryable<Something> query, string sort,
   int page, int PageSize)
{
   ...
   viewModel.Something = query.OrderByDescending(o => sort)
          .Skip((page - 1) * pageSize).Take(pageSize).ToList();
   ...
}

.OrderByDescending(o => o.AddedDate);

public MyModel GetModel(IQueryable<Something> query, Func<Something, string> sort,
   int page, int PageSize)
{
   Func<Something, string> actualSort = sort ?? (o => o.AddedDate);
   ...
   viewModel.Something = query.OrderByDescending(actualSort)
          .Skip((page - 1) * pageSize).Take(pageSize).ToList();
   ...
}

query.OrderByDescending(sort)...