网上看到的：

class Program    {        static List
    
      list = new List
     
      ()        {            new User(){ID=1,Name="Hello",Age=17,Hobby="a"},            new User(){ID=2,Name="Boy",Age=50,Hobby="z"},            new User(){ID=3,Name="Girl",Age=33,Hobby="x"},            new User(){ID=4,Name="Fox",Age=43,Hobby="b"},            new User(){ID=5,Name="Fire",Age=17,Hobby="f"},        };        static void Main(string[] args)        {            var q = list.AsQueryable().OrderBy("Name", true);            q.ToList().ForEach(x => Console.WriteLine(string.Format("ID:{0},Name:{1},Age:{2},Hobby:{3}", x.ID, x.Name, x.Age, x.Hobby)));            Console.ReadLine();        }    }    public class User    {        public int ID { get; set; }        public string Name { get; set; }        public int Age { get; set; }        public string Hobby { get; set; }    }//动态表达式    public static class Test    {                public static IQueryable
      
        OrderBy
       
        (this IQueryable
        
          source, string propertyName,bool asc = true) where TEntity : class        {            string command = asc ? "OrderBy" : "OrderByDescending";            var type = typeof(TEntity);            var property = type.GetProperty(propertyName);            var parameter = Expression.Parameter(type, "p");            var propertyAccess = Expression.MakeMemberAccess(parameter, property);            var orderByExpression = Expression.Lambda(propertyAccess, parameter);            var resultExpression = Expression.Call(typeof(Queryable), command, new Type[] { type, property.PropertyType }, source.Expression, Expression.Quote(orderByExpression));            return source.Provider.CreateQuery
         
          (resultExpression); } }