Customize Trace in ASP.NET 2.0

By default, ASP.NET 2.o provides 3 trace listeners:

1. DefaultTraceListener: Used in Visual Studio Environment
   
2. TextWriterTraceListener: redirect tracing output to an instance of the TextWriter class or to any object that is a Stream class, such as a log file, network stream, or console
   
3. EventLogTraceListener: redirect tracing messages to Windows event log
   

You can derive your customized listener from these listeners or from the abstract base class TraceListener. There are several methods you can override, but the most important ones are Write and WriteLine.

Trace configuration:
Trace can be controlled using the configuration file. The following configuration has configured an event log trace listener. All the trace information will be routed to event log named EventLogName.

<configuration>
<system.diagnostics>
<trace autoflush="true" indentsize="2">
<listeners>
<remove name="Default"/>
<add name="EventLogListener"
type="System.Diagnostics.EventLogTraceListener,System"
initializeData="MyEventLog"/>
</listeners>
</trace>
</system.diagnostics>
</configuration>

Trace switch:
Trace switch is used to filter out unwanted trace information. There are 5 levels of trace:

Off	0	Outputs no messages to Trace Listeners
Error	1	Outputs only error messages to Trace Listeners
Warning	2	Outputs error and warning messages to Trace Listeners
Info	3	Outputs informational, warning and error messages to Trace Listeners
Verbose	4	Outputs all messages to Trace Listeners

Trace switch configuration:
<system.diagnostics>
<switches>
<add name="MyTraceSwitch" value="3" />
</switches>
<trace autoflush="true" indentsize="2">
<listeners>
<add name="myListener" type="CommonLib.TextWriterTraceListener, CommonLib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=92dae50c46d5d3c2" initializeData="c:\temp\CommomLog${0:yyyy-MM-dd}.txt" />
</listeners>
</trace>
</system.diagnostics>