Filestream（讀寫）

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

namespace 讀寫文件
{
    class Program
    {
        static void Main(string[] args)
        {
            #region 讀取
            FileStream fsRead = new FileStream(@"C:\Users\Administrator\Desktop\畢畢.txt", FileMode.OpenOrCreate, FileAccess.Read);
            //定義位元組數組，每次讀取多少
            byte[] buffer = new byte[1024 * 1024 * 5];
            int r = fsRead.Read(buffer, 0, buffer.Length);//返回一共讀到的有效位元組數
            // MessageBox.Show(r.ToString());
            //將位元組數組中每一個元素按照指定的編碼格式解碼成位元組串
            string s = Encoding.UTF8.GetString(buffer, 0, r);

            //關閉流
            fsRead.Close();

            //釋放流所占用的資源
            //實際上 還是讀了5兆  只是顯示了所讀到的那些
            fsRead.Dispose();
            Console.WriteLine(s);
            Console.ReadLine();
            #endregion

            #region 寫入
            //using (FileStream fswrite = new FileStream(@"C:\Users\Administrator\Desktop\畢畢.txt", FileMode.OpenOrCreate, FileAccess.Write))
            //{
            //    //覆蓋，覆蓋所需占用的位元組量
            //    string str = "yes";
            //    byte[] buffer = Encoding.UTF8.GetBytes(str);
            //    fswrite.Write(buffer, 0, buffer.Length);
            //}
            #endregion
        }
    }
}