如何生成动态IQueryable扩展方法

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

public static class DynamicQueryableExtensions
{
    public static IQueryable<T> WhereDynamic<T>(this IQueryable<T> source, string propertyName, object value)
    {
        var parameter = Expression.Parameter(typeof(T), "x");
        var propertyAccess = Expression.PropertyOrField(parameter, propertyName);
        var constant = Expression.Constant(value);
        var condition = Expression.Equal(propertyAccess, constant);

        var lambda = Expression.Lambda<Func<T, bool>>(condition, parameter);
        return source.Where(lambda);
    }
}

// 使用示例
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 },
            new Person { Id = 3, Name = "Charlie", Age = 35 }
        }.AsQueryable();

        var filteredPeople = people.WhereDynamic("Age", 30);
        foreach (var person in filteredPeople)
        {
            Console.WriteLine(person.Name); // 输出: Alice
        }
    }
}