表达式目录树问题

Question

Expression

Answer 1

可以，用MakeMemberAccess创建表达式树。需要详细代码请先结贴。

Answer 2

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Threading.Tasks;namespace ConsoleApplication1
{
    class A
    {
        public int Age { get; set; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            var exp = buildExp<A>(20);
            Console.WriteLine(exp);
            Console.WriteLine(exp.Compile()(new A() { Age = 17 }));
        }        static Expression<Func<T, bool>> buildExp<T>(int age)
        {
            var p = Expression.Parameter(typeof(T), "x");
            var c = Expression.Constant(age, typeof(int));
            var m = Expression.MakeMemberAccess(p, typeof(T).GetMember("Age")[0]);
            var l = Expression.Lambda<Func<T, bool>>(Expression.GreaterThan(m, c), p);
            return l;
        }
    }
}x => (x.Age > 20)
False
Press any key to continue . . .