string path = AppDomain.CurrentDomain.SetupInformation.ApplicationBase + "log";
if (!Directory.Exists(path)) { Directory.CreateDirectory(path); }
path = path + $"/log{DateTime.Now.ToString("yyyyMMdd")}.log";
if (!File.Exists(path)) { File.Create(path).Dispose(); //创建完文件之后,要把资源释放掉,才能继续往文件里书写内容 }