c# - イベントログ書き込みエラー

Question

簡単ですが、イベントログに何か書きたいと思います。

protected override void OnStop()
    {
        // TODO: Add code here to perform any tear-down necessary to stop your service.
        if (!System.Diagnostics.EventLog.SourceExists("IvrService"))
        {
            System.Diagnostics.EventLog.CreateEventSource(
                "IvrService", "IvrServiceLog");
        }
        EventLog eventLog1 = new System.Diagnostics.EventLog();
        eventLog1.Source = "IvrService";
        eventLog1.Log = "IvrServiceLog";
        try
        {
            eventLog1.WriteEntry("Successfully "+State.Stopped.ToString());
            IvrApplication.StopImmediate();
        }
        catch (Exception ex)
        {
           // eventLog1.WriteEntry(ex.Message);
        }
    }

例外は次のとおりです。

   Failed to stop service. System.ArgumentException: The source 'IvrService' is not   registered in log 'IvrServiceLog'. (It is registered in log 'Application'.) " The Source   and Log properties must be matched, or you may set Log to the empty string, and it will automatically be matched to the Source property.
   at System.Diagnostics.EventLogInternal.VerifyAndCreateSource(String sourceName, String currentMachineName)
   at System.Diagnostics.EventLogInternal.WriteEntry(String message, EventLogEntryType type, Int32 eventID, Int16 category, Byte[] rawData)
   at System.Diagnostics.EventLog.WriteEntry(String message)