System.Diagnostics.Trace.Listeners
System.Diagnostics.Trace.Listeners.Clear();
System.Diagnostics.Trace.AutoFlush = true;
System.Diagnostics.Trace.Listeners.Add(new System.Diagnostics.TextWriterTraceListener("~/App_Data/app.log"));
System.Diagnostics.Trace.Listeners.Add(new System.Web.WebPageTraceListener());