C# -通过REF - WebClient类更新异步方法回调中的变量

using System;
using System.Net;

class Program
{
    static void Main()
    {
        string url = "https://example.com";
        string result = "";

        WebClient client = new WebClient();
        client.DownloadStringCompleted += (sender, e) =>
        {
            if (e.Error == null)
            {
                result = e.Result; // 更新变量
                Console.WriteLine("异步请求结果：" + result);
            }
            else
            {
                Console.WriteLine("请求发生错误：" + e.Error.Message);
            }
        };

        client.DownloadStringAsync(new Uri(url));

        // 等待异步请求完成
        Console.WriteLine("正在等待异步请求完成...");
        Console.ReadLine();
    }
}