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

I use this helper:

public static class OrderExt
{
    private static IOrderedQueryable Order(this IQueryable source, string propertyName, SortDirection descending, bool anotherLevel = false)
    {
        var param = Expression.Parameter(typeof(T), string.Empty);
        var property = Expression.PropertyOrField(param, propertyName);
        var sort = Expression.Lambda(property, param);

        var call = Expression.Call(
            typeof (Queryable),
            (!anotherLevel ? "OrderBy" : "ThenBy") +
            (descending == SortDirection.Descending ? "Descending" : string.Empty),
            new[] {typeof (T), property.Type},
            source.Expression,
            Expression.Quote(sort));

        return (IOrderedQueryable)source.Provider.CreateQuery(call);
    }
}

to call the helper, eg do this:

string sort = HttpContext.Current.Request.QueryString["sort"];
var products = _productRepository.OrderBy(sort, SortDirection.Ascending);