Unable to sort with property name in LINQ OrderBy

Question

Error is

LINQ to Entities does not recognize the method \'System.Object GetValue(System.Object, System.Object[])\' method, and this method ca

Answer 1

Just add the following extension to your code and you're good to go:

using System.Linq;
using System.Linq.Expressions;
using System;

namespace SomeNameSpace
{
    public static class SomeExtensionClass
    {
        public static IQueryable OrderByField(this IQueryable q, string SortField, bool Ascending)
        {
            var param = Expression.Parameter(typeof(T), "p");
            var prop = Expression.Property(param, SortField);
            var exp = Expression.Lambda(prop, param);
            string method = Ascending ? "OrderBy" : "OrderByDescending";
            Type[] types = new Type[] { q.ElementType, exp.Body.Type };
            var mce = Expression.Call(typeof(Queryable), method, types, q.Expression, exp);
            return q.Provider.CreateQuery(mce);
        }
    }

}

Usage:

.OrderByField(sortcriteria, true)

Edit:

For support for the ThenBy method however the following methods returning an IOrderedQueryable should take care of it all:

public static class SomeExtensionClass
{
    private static IOrderedQueryable OrderingHelper(IQueryable source, string propertyName, bool descending, bool anotherLevel)
    {
        var param = Expression.Parameter(typeof(T), "p");
        var property = Expression.PropertyOrField(param, propertyName);
        var sort = Expression.Lambda(property, param);

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

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

    public static IOrderedQueryable OrderBy(this IQueryable source, string propertyName)
    {
        return OrderingHelper(source, propertyName, false, false);
    }

    public static IOrderedQueryable OrderBy(this IQueryable source, string propertyName, bool descending)
    {
        return OrderingHelper(source, propertyName, descending, false);
    }

    public static IOrderedQueryable ThenBy(this IOrderedQueryable source, string propertyName)
    {
        return OrderingHelper(source, propertyName, false, true);
    }

    public static IOrderedQueryable ThenBy(this IOrderedQueryable source, string propertyName, bool descending)
    {
        return OrderingHelper(source, propertyName, descending, true);
    }
}