错误日志

public static void WriteLog(string msg) {
			if (string.IsNullOrEmpty(_writelog)) {
				_writelog = getAppSetting("writelog");
			}
			if (_writelog != "yes") {
				return;
			}

			string p = System.Web.HttpContext.Current.Server.MapPath("logs");
			if (!Directory.Exists(p)) Directory.CreateDirectory(p);
			StreamWriter wr = new StreamWriter(string.Format("{0}\\{1:yyyyMMdd}.txt", p, DateTime.Today), true);
			wr.WriteLine(string.Format("{0:yyyy-MM-dd HH:mm:ss.ffff} {1}", DateTime.Now, msg));
			wr.Close();
		}

这种方法在global中会出现未将对象引用到示例的错误  原因是global中没有上下文，所以不能用HttpContext类了
但是能这种方法

string p = System.Web.HttpContext.Current.Server.MapPath("logs");==》string p=AppDamin.CurrentDomain.BaseDirectory+"logs";