自己写一个Log类

 public class MyLogger

    {

        public static void Log(string str)

        {

            StreamWriter sw = null;

            try

            {

                DirectoryInfo di = new DirectoryInfo(@"D:\testing");//获取D:\testing 目录的信息

                if (!di.Exists)//如果没有该目录，则直接创建一个

                {

                    di.Create();

                }

                FileInfo fileInfo = new FileInfo(@"D:\testing\test.txt");//获取 D:\testing\test.txt 文本的信息

                if (!fileInfo.Exists)//同样的，如果没有该文件，则直接创建一个，注意使用CreateText创建完同时返回 StreamWriter 流

                {

                    sw = fileInfo.CreateText();

                }

                else

                {

                    sw = fileInfo.AppendText(); //存在该文件，则对该文件流进行写入叠加操作（即不覆盖掉之前写的东西）

                }

                sw.WriteLine(str);

                sw.Flush(); //注意关闭文件流

                sw.Close();

                sw.Dispose();

            }

            catch (Exception ex)

            {

                if (sw != null)

                {

                    sw.Close();

                    sw.Flush();

                    sw = null;

                }



            }

        }

    }

调用

 MyLogger.Log("tesing......");

 

 

把整个Exception类传递给一个方法

 /// <summary>

        /// 写错误日志

        /// </summary>

        /// <param name="objErr"></param>

        /// <param name="context"></param>

        public void WriteErrorLog(Exception objErr)

        {

            HttpContext context = HttpContext.Current;

            //Exception objErr = context.Server.GetLastError().GetBaseException();

            string strError = string.Empty;

            strError += "用户IP:" + context.Request.UserHostAddress + "\r\n";

            strError += "发生时间:" + System.DateTime.Now.ToString() + "\r\n";

            strError += "发生异常页: " + context.Request.Url.ToString() + "\r\n";

            strError += "异常信息: " + objErr.Message + "\r\n";

            strError += "异常方法: " + objErr.TargetSite + "\r\n";

            strError += "错误源:" + objErr.Source + "\r\n";

            strError += "错误堆栈信息:" + objErr.StackTrace + "\r\n";

            strError += "----------------------------------------------------------------------------------------------\r\n";



            //独占方式，因为文件只能由一个进程写入.

            System.IO.StreamWriter writer = null;

            try

            {

                lock (this)

                {

                    

                    // 写入日志

                    string year = DateTime.Now.Year.ToString(),

                           month = DateTime.Now.Month.ToString();

                    string filename = DateTime.Now.Day.ToString() + ".txt";

                    string path = context.Server.MapPath("~/Error/") + year + "/" + month;

                    //如果目录不存在则创建

                    if (!System.IO.Directory.Exists(path))

                    {

                        System.IO.Directory.CreateDirectory(path);

                    }

                    System.IO.FileInfo file = new System.IO.FileInfo(path + "/" + filename);



                    writer = new System.IO.StreamWriter(file.FullName, true);//文件不存在就创建,true表示追加

                    writer.Write(strError);

                }

            }

            catch

            {

                context.Response.Redirect("~/Error.html");

            }

            finally

            {

                if (writer != null)

                { writer.Flush(); writer.Close(); }

            }

        }

 

建议：

　　如非必要，Logger不要自己写，用Nlog或者log4net等第三方成熟控件。