C# Exception 写入文件

 /// <summary>
        /// 将异常打印到LOG文件
        /// </summary>
        /// <param name="ex">异常</param>
        public static void WriteLog(Exception ex)
        {
            //如果日志文件为空，则默认在Debug目录下新建YYYY-mm-dd_Log.log文件
           string LogAddress = Environment.CurrentDirectory + '\'
                + DateTime.Now.Year.ToString()
                + DateTime.Now.Month.ToString()
                + DateTime.Now.Day.ToString() + "_Log.log";
           if (!File.Exists(LogAddress))
           {
               FileStream fs = new FileStream(LogAddress, FileMode.Create, FileAccess.Write);
               //把异常信息输出到文件
               StreamWriter sw = new StreamWriter(fs, Encoding.UTF8);
               sw.WriteLine("当前时间：" + DateTime.Now.ToString());
               sw.WriteLine("异常信息：" + ex.Message);
               sw.WriteLine("异常对象：" + ex.Source);
               sw.WriteLine("调用堆栈：" + ex.StackTrace.Trim());
               sw.WriteLine("触发方法：" + ex.TargetSite);
               sw.WriteLine();
               
               sw.Close();
               fs.Close();
           }
           else
           {
               //把异常信息输出到文件
               FileStream fs = new FileStream(LogAddress,FileMode.Open,FileAccess.Write);
               StreamWriter sw = new StreamWriter(fs);
               sw.WriteLine("当前时间：" + DateTime.Now.ToString());
               sw.WriteLine("异常信息：" + ex.Message);
               sw.WriteLine("异常对象：" + ex.Source);
               sw.WriteLine("调用堆栈：" + ex.StackTrace.Trim());
               sw.WriteLine("触发方法：" + ex.TargetSite);
               sw.WriteLine();
               
               sw.Close();
               fs.Close();
           }
        }