使用LINQ将两个实体合并为一个实体

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

public class EntityA
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class EntityB
{
    public int Id { get; set; }
    public int EntityAId { get; set; }
    public string Description { get; set; }
}

public class MergedEntity
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

public class Program
{
    public static void Main()
    {
        List<EntityA> entitiesA = new List<EntityA>()
        {
            new EntityA { Id = 1, Name = "Entity A 1" },
            new EntityA { Id = 2, Name = "Entity A 2" },
            new EntityA { Id = 3, Name = "Entity A 3" }
        };

        List<EntityB> entitiesB = new List<EntityB>()
        {
            new EntityB { Id = 1, EntityAId = 1, Description = "Description 1" },
            new EntityB { Id = 2, EntityAId = 2, Description = "Description 2" },
            new EntityB { Id = 3, EntityAId = 3, Description = "Description 3" }
        };

        var mergedEntities = from a in entitiesA
                             join b in entitiesB on a.Id equals b.EntityAId
                             select new MergedEntity
                             {
                                 Id = a.Id,
                                 Name = a.Name,
                                 Description = b.Description
                             };

        foreach (var entity in mergedEntities)
        {
            Console.WriteLine($"Id: {entity.Id}, Name: {entity.Name}, Description: {entity.Description}");
        }
    }
}