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


namespace 读取host文件
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void button1_Click(object sender, EventArgs e)
        {
            string str;
            StreamReader sr = new StreamReader(@"C:\windows\system32\drivers\etc" + "\\hosts", false);
            str = sr.ReadToEnd().ToString();
            sr.Close();
            this.richTextBox1.Text = str;///读取

        }

   }

}

@"C:\windows\system32\drivers\etc" + "\\hosts"文件路径