string filename = @"C:\Windows\System32\Hi.bin";
             if (!File.Exists(filename))
            {
                FileStream fs;
                fs = new FileStream(filename, FileMode.Create);
                fs.Close();
            }
            else
            {
                FileStream fs;
                //创建文件流
                fs = new FileStream(filename, FileMode.Open);
                fs.Close();
            }