C#文件流FileStream

using System.IO;//必须包含此命令空间  

      static void Main(string[] args)
        {
            byte[] byteFile = new byte[30];
            char[] charFile = new char[30];
            string path = @"D:\TEST.txt";
            FileStream fe = new FileStream(path,FileMode.OpenOrCreate,FileAccess.ReadWrite);//实例化FileStream
            fe.Seek(0,SeekOrigin.Begin);
            fe.Read(byteFile,0, byteFile.Length);//读取TXT文件
            Decoder dc = Encoding.Default.GetDecoder();
            dc.GetChars(byteFile,0, byteFile.Length,charFile,0,true);
            Console.WriteLine(charFile);

            charFile = "世界人民大团结万岁~！".ToCharArray();//写入数字串。
            Encoder en = Encoding.Default.GetEncoder();
            en.GetBytes(charFile, 0, charFile.Length, byteFile, 0, true);
            fe.Seek(0, SeekOrigin.Begin);
            fe.Write(byteFile, 0, byteFile.Length);
 
            Console.ReadKey();


        }