换个控件--RichTextBox的WordWrap属性为true

不用listbox行不，换成textbox

如果问题得到解决，请点我回答左上角的采纳

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Net;

namespace Q754071
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private IEnumerable<string> autowarp(string s, int maxlen)
        {
            foreach (var item in s.Split(new string[] { "\r\n" }, StringSplitOptions.None))
            {
                string remain = item;
                while (remain.Length > maxlen)
                {
                    yield return remain.Substring(0, maxlen);
                    remain = remain.Substring(maxlen);
                }
                yield return remain;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            WebClient wc = new WebClient();
            string s = Encoding.GetEncoding("utf-8").GetString(wc.DownloadData("https://www.baidu.com"));
            foreach (var item in autowarp(s, 80))
                listBox1.Items.Add(item);
        }
    }
}