使用linq连接两个属性，然后转换为逗号分隔的字符串

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

public class MyClass
{
    public string PropertyA { get; set; }
    public string PropertyB { get; set; }
}

public class Program
{
    public static void Main()
    {
        List<MyClass> myObjects = new List<MyClass>
        {
            new MyClass { PropertyA = "A1", PropertyB = "B1" },
            new MyClass { PropertyA = "A2", PropertyB = "B2" },
            new MyClass { PropertyA = "A3", PropertyB = "B3" }
        };

        List<string> result = myObjects.Select(obj => obj.PropertyA + "," + obj.PropertyB).ToList();

        string joinedString = string.Join(",", result);

        Console.WriteLine(joinedString);
    }
}