读写文件

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;



namespace FileStreamRead

{

    class StreamReadDemo01

    {

        public StreamReadDemo01() { }

        /// <summary>

        /// 一个字节一个字节的读

        /// </summary>

        public void ReadFile()

        {

            FileStream fs;

            string enPath = Environment.CurrentDirectory.Substring(0, Environment.CurrentDirectory.Length - 9);

            string readPath = enPath + "TextFile1.txt";



            fs = new FileStream(readPath, FileMode.Open);

            long left = fs.Length;

            byte[] bt = new byte[100];//一点一点读取数据很好，就是字的大小不好控制

            //char[] bt = new char[100];

            int maxLength = bt.Length;

            int start = 0;

            int num = 0;

            while (left > 0)

            {

                fs.Position = start;

                num = 0;

                if (left < maxLength)

                {

                    num = fs.Read(bt, 0, Convert.ToInt32(left));

                }

                else

                {

                    num = fs.Read(bt, 0, maxLength);

                }

                if (num == 0)

                {

                    break;

                }

                start += num;

                left -= num;

                Console.Write(Encoding.UTF8.GetString(bt));

            }

            fs.Close();

        }

        string readLine = "";

        /// <summary>

        /// 一行一行的读

        /// </summary>

        public void StringRead()

        {

            string enPath = Environment.CurrentDirectory.Substring(0, Environment.CurrentDirectory.Length - 9);

            string readPath = enPath + "TextFile1.txt";

            StreamReader sr = new StreamReader(readPath, Encoding.GetEncoding("GB2312"));



            string line;

            //string readLine="";

            while ((line = sr.ReadLine()) != null)

            {

                readLine += line.ToString() + "\r\n";

            }

            Console.Write(readLine);

            sr.Close();

        }

        /// <summary>

        /// 写文件

        /// </summary>

        public void StringWriter()

        {

            string enPath = Environment.CurrentDirectory.Substring(0, Environment.CurrentDirectory.Length - 9);

            string readPath = enPath + "TextFile2.txt";

            StreamWriter sw = new StreamWriter(readPath,true, Encoding.UTF8);

           // sw.WriteLine(readLine);

            sw.Write(readLine);//这两句读出来几乎一模一样

            sw.Close();

        }

    }

}