.net的四位域名多吗

using System;
using System.Net;

class Program
{
    static void Main()
    {
        string domain = "abcd.com";
        if (IsDomainAvailable(domain))
        {
            Console.WriteLine($"{domain} is available!");
        }
        else
        {
            Console.WriteLine($"{domain} is not available.");
        }
    }

    static bool IsDomainAvailable(string domain)
    {
        try
        {
            using (WebClient client = new WebClient())
            {
                client.DownloadString($"http://{domain}");
                return false; // If no exception, domain is not available
            }
        }
        catch (WebException)
        {
            return true; // Exception indicates domain might be available
        }
    }
}