在运行时动态选择LINQ选择字段

using System;
using System.Linq;
using System.Linq.Expressions;

public class Person
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
}

public class Program
{
    public static void Main()
    {
        var people = new List<Person>
        {
            new Person { Id = 1, Name = "Alice", Age = 30 },
            new Person { Id = 2, Name = "Bob", Age = 25 }
        };

        var selectedFields = new[] { "Name" }; // 这里可以是运行时决定的字段列表

        var parameter = Expression.Parameter(typeof(Person), "p");
        var propertyAccessors = selectedFields.Select(fieldName =>
            (Expression)Expression.Property(parameter, typeof(Person).GetProperty(fieldName)));

        var selector = Expression.Lambda(Expression.New(typeof(object[]), propertyAccessors), parameter);

        var lambda = (Func<Person, object[]>)selector.Compile();

        var results = people.Select(lambda).ToList();

        foreach (var result in results)
        {
            Console.WriteLine(string.Join(", ", ((object[])result).Select((o, i) => $"{selectedFields[i]}: {o}")));
        }
    }
}