C#中FileStream

1.写文件

 

FileStream fs = new FileStream(@"E:/新建文件夹/sss.txt", FileMode.OpenOrCreate, FileAccess.Write);
            byte[] buffer = Encoding.UTF8.GetBytes(Txt1);
            fs.Position = fs.Length;//设置流的位置，防止覆盖，设置书写位置为末尾
            fs.Write(buffer,0, buffer.Length);
            fs.Flush();
            fs.Close();

 

2.读文件

         StringBuilder sb = new StringBuilder();
            //读取数据文件
            using (FileStream fsRead = new FileStream(@"E:/新建文件夹/OriginalData.dat", FileMode.OpenOrCreate, FileAccess.Read))
            {
                long otherLength = fsRead.Length;//还没读取的文件长度
                byte[] buffer = new byte[128];//接收文件的字节数组
                int num = 0;//实际读取的字节数
                int readStartPosit = 0;//开始读取的位置
                while (readStartPosit < 256)
                {
                    fsRead.Position = readStartPosit;//设置文件读取的位置
                    if (otherLength < buffer.Length)//当剩余文件小于最大读取时
                    {
                      num=  fsRead.Read(buffer, readStartPosit, Convert.ToInt32(otherLength));
                    }
                    else
                    {
                      num=  fsRead.Read(buffer, 0, buffer.Length);
                    }
                    if (num <= 0) break;

                    otherLength -= num;
                    readStartPosit += num;
                    sb.Append(Encoding.UTF8.GetString(buffer));
                }
            }
            Txt1 = sb.ToString();