linq orderby 后面怎么使用动态参数_ASP.NET

linq orderby 后面如何使用动态参数？
string ob = "f.Name";
var abc = from f in files
orderby(ob)
select f;

其中，orderby(ob) 显然不工作，怎么解决？

实际应用时，我要根据gridview的column header来排序，所以要pass header text 到 linq,然后再绑定gridview.

------解决方案--------------------------------------------------------
如果用的多得话，可以看看下面的库

Dynamic LINQ (Part 1: Using the LINQ Dynamic Query Library)
http://weblogs.asp.net/scottgu/archive/2008/01/07/dynamic-linq-part-1-using-the-linq-dynamic-query-library.aspx
------解决方案--------------------------------------------------------

C# code

    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();        }
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这个用反射即可解决嘛

linq 实现动态 orderby 

OR:

Dynamic LINQ