using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace ConsoleApplication2
{
    class Class2
    {
        public const string path = "C:/Users/dajun/Desktop/C#/xdj/gadata.txt";
        static void Main(string[] args)
        {
            //string path = "C:/Users/dajun/Desktop/C#/xdj/gadata.txt";
            try
            {
                //FileStream aFile = new FileStream(path, FileMode.Open);// 方式一
                //StreamReader sr = new StreamReader(aFile);
                StreamReader sr = new StreamReader(path); //方式二

                string strLine = sr.ReadLine();
                //Read data in line by line 
                while (strLine != null)
                {
                    Console.WriteLine(strLine);
                    strLine = sr.ReadLine();
                }
                sr.Close();
            }
            catch (IOException ex)
            {
                Console.WriteLine("An IOException has been thrown!");
                Console.WriteLine(ex.ToString());
                Console.ReadLine();
                return;
            }
        }
    }
}

                int nChar;
                nChar = sr.Read();
                while (nChar != -1)
                {
                    //Console.Write(nChar);
                    Console.Write(Convert.ToChar(nChar));
                    //Console.WriteLine("{0}",nChar);
                    nChar = sr.Read();
                }
                sr.Close();