Linq-to-Entities Dynamic sorting

Question

This is my query, how can I use string as orderby parameter?

string sortColumn=\"Title\";

var  items = (from ltem in ctxModel.Items
              where ltem.Ite         


        

Answer 1

Here's another alternative, the EntitySorter. Allows a bit what dynamic LINQ does with strings, but wraps the operation in a object, just like with the Query Object pattern. It allows both sorting by strings, and by type safe constructs. Here are some examples:

// Ways of defining an entity sorter
// 1. Using strings:
IEntitySorter sorter = EntitySorter
    .OrderBy("Address.City")
    .ThenByDescending("Id");

// 2. Defining a sorter with lambda's
IEntitySorter sorter = EntitySorter
    .OrderByDescending(p => p.Name)
    .ThenBy(p => p.Id)
    .ThenByDescending(p => p.Address.City);

// 3. Using a LINQ query
IEntitySorter sorter =
    from person in EntitySorter.AsQueryable()
    orderby person.Name descending, person.Address.City
    select person;

// And you can pass a sorter from your presentation layer
// to your business layer, and you business layer may look
// like this:
static Person[] GetAllPersons(IEntitySorter sorter)
{
    using (var db = ContextFactory.CreateContext())
    {
        IOrderedQueryable sortedList =
            sorter.Sort(db.Persons);

        return sortedList.ToArray();
    }
}

You can find the code here.