Writing Diagnostic Information to Event Log / SharePoint Log

LogMessage(string.Format("SP group '{0}' does not have enough permission.", NewItServiceAdminGroupName),
           EventLogEntryType.Error, true, "Feature Activation", EventSeverity.ErrorCritical,
           TraceSeverity.Unexpected);

/// <summary>
/// Log message to event log and SharePoint log.
/// </summary>
/// <param name="message">Message to log.</param>
/// <param name="eventLogEntryType">Specifies the type of event entry log.</param>
/// <param name="logInSharePointLog">Flag to include SharePoint log entry as well.</param>
/// <param name="eventCategoryName">SharePoint event category name.</param>
/// <param name="eventSeverity">SharePoint event severity.</param>
/// <param name="traceSeverity">SharePoint trace severity.</param>
public static void LogMessage(string message, EventLogEntryType eventLogEntryType, bool logInSharePointLog, string eventCategoryName, EventSeverity eventSeverity, TraceSeverity traceSeverity)
{
    SPSecurity.RunWithElevatedPrivileges(delegate()
    {
        const string sourceName = "SharePoint Custom Solutions";
        const string logName = "Application";

        if (!EventLog.SourceExists(sourceName))
        {
            EventLog.CreateEventSource(sourceName, logName);
        }

        // Writing to -> Windows Logs/Application
        EventLog.WriteEntry(sourceName, message, eventLogEntryType, 1001, 100);

        if (logInSharePointLog)
        {
            SPDiagnosticsService diagnosticsService = SPDiagnosticsService.Local;
            SPDiagnosticsCategory categoryOfTheTrace = diagnosticsService.Areas["SharePoint Foundation"].Categories["Unknown"];

            SPDiagnosticsService.Local.WriteTrace(1, categoryOfTheTrace, traceSeverity, message, categoryOfTheTrace.Name, categoryOfTheTrace.Area.Name);
        }
    });
}