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

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

            WebRequest wrq = WebRequest.Create("http://www.);
            WebResponse wrs = wrq.GetResponse();
            Stream strm = wrs.GetResponseStream();
            StreamReader sr = new StreamReader(strm);
            string line;
            while ((line = sr.ReadLine()) != null) ;
            {
                listBox1.Items.Add(line);// 这里有个错误说是Items参数值不能为空 求解释
            }
            strm.Close();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

就是说参数line为空值 null

为赋值，string line 改写成string line="";就可以了

写错字了 未赋值

3q

改了 还是不对

说明你的LINE 的值为空值，调试一下看看