EF dynamically implements lambda expressions

Ascending and descending judgment:
            //Implement a part of
ParameterExpression pe=Expression.Parameter(typeof(User_sc), "a");


            //Implement the part after >
var ep=Expression.Property(pe, px);


            //Merge into a =>a.min like
Expression<Func<User_sc, object>> cc = Expression.Lambda<Func<User_sc, object>>(ep, pe);