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A realtime event log monitoring tool

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27 Aug 2003CPOL2 min read 369.7K   11.7K   110   73
Demonstrates how to do realtime event log monitoring

Image 1

Introduction

I'm an instant gratification kind of person. I like to see who and from where my machine is being accessed, as it occurs. This tool allows you to do just that and provides a number of other event log monitoring capabilities.

Background

While testing a piece of software that provides Windows event logging, our QA team questioned if there was a way to monitor events as they are written to the Windows event log, hence the creation of this little utility. The notifications that the tool displays are done so using the most-excellent NotifyIconEx class by Joel Matthias.

Capturing Events

The EventLog class contains an event handler called EntryWritten. This handler expects an argument of type EntryWrittenEventArgs. To capture events as they happen, we simply set the EnableRaisingEvents property to true and declare the method name that will handle the event.

C#
private void StartWatch()
{      
  EventLog myLog = new EventLog(watchLog);
        
  // set event handler
  myLog.EntryWritten += new EntryWrittenEventHandler(OnEntryWritten);
  myLog.EnableRaisingEvents = true;
}

Displaying Events

When events that match the specified criteria occur, a balloon notification is displayed with the details of the last event that was written. (To capture and display Security log events, you must have auditing turned on.)

C#
private void OnEntryWritten(object source, EntryWrittenEventArgs e)
{
  string logName = watchLog;
  GetLogEntryStats(watchLog);
  
  if (logType == eventFilter || eventFilter.Length == 0)
  {
    // show balloon
    NotifyIcon.ShowBalloon("Event Log Monitor",
      "An event was written to the "+logName+" event log."+
      "\nType: "+LogType+
      "\nSource: "+LogSource+
      "\nCategory: "+LogCategory+
      "\nEventID: "+EventID+
      "\nUser: "+User,
      NotifyIconEx.NotifyInfoFlags.Info,
      5000);
        
    LogNotification();
  }
}
    
private void GetLogEntryStats(string logName)
{
  int e = 0;
  
  EventLog log = new EventLog(logName);
  e = log.Entries.Count - 1; // last entry

  logMessage = log.Entries[e].Message;
  logMachine = log.Entries[e].MachineName;
  logSource = log.Entries[e].Source;
  logCategory = log.Entries[e].Category;
  logType = Convert.ToString(log.Entries[e].EntryType);
  eventID = log.Entries[e].EventID.ToString();
  user = log.Entries[e].UserName;
  logTime = log.Entries[e].TimeGenerated.ToShortTimeString();
  log.Close();  // close log
}

The GetEventLogs() method provides an overload for retrieving the logs from a remote machine. It is feasible to assume that event monitoring should work the same on a remote machine as it does on the local computer, given the appropriate permissions. As time permits, I'll be expanding the filtering capabilities of the tool and provide the ability to monitor multiple machines.

Compatibility Issues

The code has only been tested on Windows XP SP1 but should run on Windows 2000. However, while the NotifyIconEx class contains an event handler called BalloonClick, this isn't supported on Windows 2000. Will not work on Win9x or NT4 as they are incapable of displaying balloon notifications.

History

  • Version 1.0 - 08.22.2003

  • License

    This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


    Written By
    Zambia Zambia
    Living abroad and loving life.

    Comments and Discussions

     
    GeneralA little help with a modification I made to your app.. Pin
    gonepostal55528-Jun-06 6:31
    gonepostal55528-Jun-06 6:31 
    GeneralRe: A little help with a modification I made to your app.. Pin
    Jim Weiler7-Sep-07 17:18
    Jim Weiler7-Sep-07 17:18 
    Generalnotification on error event only Pin
    c-a-b-9-Mar-06 2:09
    c-a-b-9-Mar-06 2:09 
    GeneralRe: notification on error event only Pin
    Jonnystar21-Mar-06 10:57
    Jonnystar21-Mar-06 10:57 
    QuestionMultiple logs? Pin
    celtboy30-Oct-05 15:49
    celtboy30-Oct-05 15:49 
    AnswerRe: Multiple logs? Pin
    Jonnystar21-Mar-06 11:01
    Jonnystar21-Mar-06 11:01 
    QuestionAppropriate Permissions? Pin
    JVMFX20-Oct-05 3:12
    JVMFX20-Oct-05 3:12 
    AnswerRe: Appropriate Permissions? Pin
    Christian Merritt20-Oct-05 3:37
    Christian Merritt20-Oct-05 3:37 
    If you want to log an event to the eventlog on a remote machine, the process you are using must have "Access this computer from the network" and "Log on locally" permissions on the remote machine.

    Additionally, if you are creating a new event source, the process must also have Write access to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Eventlog\ registry section.

    The following article also gives some insight to your question: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnpag2/html/PAGHT000015.asp

    -- modified at 9:38 Thursday 20th October, 2005
    GeneralLimitations Pin
    Los Guapos22-Dec-04 3:30
    Los Guapos22-Dec-04 3:30 
    GeneralRe: Limitations Pin
    dm218-Apr-05 8:27
    dm218-Apr-05 8:27 
    GeneralRe: Limitations Pin
    Jonnystar21-Mar-06 11:05
    Jonnystar21-Mar-06 11:05 
    GeneralProblem with the monitoring tool Pin
    pat27088128-Jul-04 6:38
    pat27088128-Jul-04 6:38 
    GeneralRe: Problem with the monitoring tool Pin
    Christian Merritt28-Jul-04 8:00
    Christian Merritt28-Jul-04 8:00 
    GeneralRe: Problem with the monitoring tool Pin
    pat27088128-Jul-04 8:13
    pat27088128-Jul-04 8:13 
    GeneralRe: Problem with the monitoring tool Pin
    Christian Merritt28-Jul-04 10:06
    Christian Merritt28-Jul-04 10:06 
    GeneralRe: Problem with the monitoring tool Pin
    pat27088128-Jul-04 10:09
    pat27088128-Jul-04 10:09 
    GeneralRe: Problem with the monitoring tool Pin
    pat27088128-Jul-04 22:19
    pat27088128-Jul-04 22:19 
    GeneralRe: Problem with the monitoring tool Pin
    pat27088128-Jul-04 22:59
    pat27088128-Jul-04 22:59 
    GeneralRe: Problem with the monitoring tool Pin
    pat27088130-Jul-04 22:12
    pat27088130-Jul-04 22:12 
    GeneralRe: Problem with the monitoring tool Pin
    Christian Merritt1-Aug-04 6:13
    Christian Merritt1-Aug-04 6:13 
    GeneralRe: Problem with the monitoring tool Pin
    pat2708811-Aug-04 11:05
    pat2708811-Aug-04 11:05 
    GeneralRe: Problem with the monitoring tool Pin
    Christian Merritt2-Aug-04 16:02
    Christian Merritt2-Aug-04 16:02 
    GeneralRe: Problem with the monitoring tool Pin
    pat2708812-Aug-04 21:28
    pat2708812-Aug-04 21:28 
    GeneralRe: Problem with the monitoring tool Pin
    Christian Merritt3-Aug-04 3:01
    Christian Merritt3-Aug-04 3:01 
    GeneralRe: Problem with the monitoring tool Pin
    pat2708811-Aug-04 10:58
    pat2708811-Aug-04 10:58 

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