LINQ IE无数订购

Question

I'm trying to implement filtering/ordering/paging on a data set. I want to filter by a search string, then apply ordering, then select a subset of that set to be a page.

Code looks like:

IEnumerable<Manufacturer> manufacturers;

if (!String.IsNullOrEmpty(genericSearch))
{
    manufacturers = db.Manufacturers.Where(l => l.Name.Contains(genericSearch));
}

manufacturers = manufacturers.OrderBy(sortColName, sortDir, true); // this won't build. it would
// build if i put 'db.Manufacturers' before the .OrderBy but then i lose my filter. it would 
// also build if i used 'l => l.Name' as the OrderBy parameter but i only have the column name 
//as a string from the client.

manufacturers.Skip(displayStart).Take(displayLength).ToList().ForEach(rec => aaData.Add
 (rec.PropertiesToList())); // this is paging where i can use ToList()

How do I do this to allow ordering with the column name as a string?

Answer 1

One of the possible ways to use reflection

   public static IEnumerable<T> Sort<T>(this IEnumerable<T> list,
            string column, SortDirection direction = SortDirection.Ascending)
   {
        Func<T, object> selector = p => p.GetType().GetProperty(column).GetValue(p, null);
        return (direction == SortDirection.Ascending
                    ? list.OrderBy(selector)
                    : list.OrderByDescending(selector)
                    );
   }