相关疑难解决方法(0)

我想在动态LINQ查询中使用枚举.

是否可能,如果,如何？

考虑下面的代码:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Dynamic;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            Room aRoom = new Room() { Name = "a Room" };
            Room bRoom = new Room() { Name = "b Room" };
            Room cRoom = new Room() { Name = "c Room" };

            House myHouse = new House
            {
                Rooms = new List<Room>(new Room[] { aRoom }),
                MainRoom = aRoom
            };
            House yourHouse = new House()
            {
                Rooms …

我正在尝试实现这个如何在Linq where子句中指定动态字段名称？并得到一个编译器错误,说:

无法解析方法'Where(System.Linq.Expressions.LambdaExpression

public class Employee
{
    public string Name { get; private set; }
    public int Salary { get; private set; }

    public Employee(string name, int salary)
    {
        Name = name;
        Salary = salary;
    }
}

然后在控制台应用程序的主要方法

var employees = new List<Employee>
{
    new Employee("Bob", 45000),
    new Employee("Jane", 25000),
    new Employee("Jim", 5)
};

var eParam = Expression.Parameter(typeof(Employee), "e");

var comparison = Expression.Lambda(
    Expression.LessThan(
        Expression.Property(eParam, "Salary"),
        Expression.Constant(40000)),
    eParam);
var c = from e in employees.Where(comparison) // COMPILER ERROR …