未获得从HttpWebResponse提取正文的正确编码

using System;
using System.IO;
using System.Net;
using System.Text;

public class Program
{
    public static void Main()
    {
        string url = "https://www.example.com"; // 替换为实际的URL

        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();

        string encodingName = GetEncodingFromContentType(response.ContentType);
        Encoding encoding = GetEncoding(encodingName);

        string responseBody = ReadResponseBody(response, encoding);

        Console.WriteLine(responseBody);
    }

    private static string GetEncodingFromContentType(string contentType)
    {
        string encodingName = "UTF-8"; // 默认编码

        if (!string.IsNullOrEmpty(contentType))
        {
            int charsetIndex = contentType.IndexOf("charset=", StringComparison.OrdinalIgnoreCase);
            if (charsetIndex >= 0)
            {
                encodingName = contentType.Substring(charsetIndex + 8).Trim();
            }
        }

        return encodingName;
    }

    private static Encoding GetEncoding(string encodingName)
    {
        Encoding encoding = Encoding.UTF8; // 默认编码

        try
        {
            encoding = Encoding.GetEncoding(encodingName);
        }
        catch (ArgumentException)
        {
            // 如果指定的编码无效，则使用默认编码
        }

        return encoding;
    }

    private static string ReadResponseBody(HttpWebResponse response, Encoding encoding)
    {
        using (Stream responseStream = response.GetResponseStream())
        {
            using (StreamReader reader = new StreamReader(responseStream, encoding))
            {
                return reader.ReadToEnd();
            }
        }
    }
}