有时候，日志输出的时候会根据时间来分类，譬如“20140821\trace.log”，在Enterprise Library中通过工具配置，只能定义日志文件名称，可以通过代码修改FlatFileTraceListenerData实现或Custom Trace Listener方式，

通过代码修改FlatFileTraceListenerData实现代码如下：

        public static string GetTraceLogPath(string listenersName)        {            string _tracePath = string.Empty;            if (!string.IsNullOrEmpty(listenersName))            {                Configuration _etlConfig = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);                LoggingSettings _loggingSettings = (LoggingSettings)_etlConfig.GetSection(LoggingSettings.SectionName);                FlatFileTraceListenerData _listeners = _loggingSettings.TraceListeners.Get(listenersName) as FlatFileTraceListenerData;                if (_listeners != null)                {                    _tracePath = _listeners.FileName;                }            }            return _tracePath;        }        public static void SetTraceLogPath(string listenersName, string fileName)        {            if (!string.IsNullOrEmpty(listenersName) && !string.IsNullOrEmpty(fileName))            {                Configuration _etlConfig = ConfigurationManager.OpenExeConfiguration(System.Configuration.ConfigurationUserLevel.None);                LoggingSettings _loggingSettings = (LoggingSettings)_etlConfig.GetSection(LoggingSettings.SectionName);                FlatFileTraceListenerData _listeners = _loggingSettings.TraceListeners.Get(listenersName) as FlatFileTraceListenerData;                if (_listeners != null)                {                    _listeners.FileName = fileName;                    _etlConfig.Save();                }            }        }

测试代码：

            try            {                string _listenName = "FlatFile TraceListener";                SetTraceLogPath(_listenName, string.Format(@"{0}/trace.log", DateTime.Now.ToString("yyyyMMdd")));                LogEntry log = new LogEntry();                log.Categories.Add("Warning");                log.Title = "测试";                log.Message = "日志日志内容";                Logger.Write(log);                LogEntry log2 = new LogEntry();                log2.Categories.Add("Warning");                log2.Title = "测试2";                log2.Message = "日志日志内容2";                Logger.Write(log2);                Console.WriteLine(GetTraceLogPath(_listenName));            }            catch (Exception ex)            {                Console.WriteLine(ex.Message);            }            finally            {                Console.ReadLine();            }

<style type="text/css">.csharpcode, .csharpcode pre{ font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/}.csharpcode pre { margin: 0em; }.csharpcode .rem { color: #008000; }.csharpcode .kwrd { color: #0000ff; }.csharpcode .str { color: #006080; }.csharpcode .op { color: #0000c0; }.csharpcode .preproc { color: #cc6633; }.csharpcode .asp { background-color: #ffff00; }.csharpcode .html { color: #800000; }.csharpcode .attr { color: #ff0000; }.csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em;}.csharpcode .lnum { color: #606060; }</style>测试效果：

希望有所帮助