public class TestD
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }
        public static IQueryable<T> OrderSort<T>(IQueryable<T> Sour, string SortExpression, string Direction)
        {
            string SortDirection = string.Empty;
            if (Direction == "asc")
                SortDirection = "OrderBy";
            else if (Direction == "desc")
                SortDirection = "OrderByDescending";
            ParameterExpression pe = Expression.Parameter(typeof(T), SortExpression);
            PropertyInfo pi = typeof(T).GetProperty(SortExpression);
            Type[] types = new Type[2];
            types[0] = typeof(T);
            types[1] = pi.PropertyType;
            Expression expr = Expression.Call(typeof(Queryable), SortDirection, types, Sour.Expression, Expression.Lambda(Expression.Property(pe, SortExpression), pe));
            IQueryable<T> query = Sour.Provider.CreateQuery<T>(expr);
            return query;
        }
       static void Main(string[] args)
        {
            List<TestD> list = new List<TestD>() { new TestD() { ID = 1, Name = "a" }, new TestD() { ID = 2, Name = "b" } };
            var linq = (from l in list select l).AsQueryable<TestD>();
            OrderSort<TestD>(linq, "ID", "desc").ToList<TestD>().ForEach(x => Console.WriteLine("{0} {1}", x.ID, x.Name));
            Console.ReadLine();
        }

------解决方案--------------------
这个用反射即可解决嘛

linq 实现动态 orderby 

OR:

Dynamic LINQ