Заявление:
private static TraceSource _traceSource = new TraceSource("YourSourceName");
Использование, см. MSDN :
_traceSource.TraceEvent(...);
Конфигурация:
<system.diagnostics>
<sources>
<source name="YourSourceName" switchValue="All" switchType="System.Diagnostics.SourceSwitch">
<listeners>
<add name="eventLog" />
</listeners>
</source>
<trace autoflush="true">
<listeners>
<add name="eventLog" />
</listeners>
</trace>
<sharedListeners>
<add name="eventLog" type="System.Diagnostics.EventLogTraceListener" initializeData="SourceName" />
</sharedListeners>
</system.diagnostics>