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A realtime event log monitoring tool

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27 Aug 2003CPOL2 min read 375.4K   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

     
    Questionwatch all 3 logs + display full log entry Pin
    Chris Blue10-Aug-07 10:24
    Chris Blue10-Aug-07 10:24 
    General=== pleeeeease === Pin
    Chris Blue29-Mar-07 19:09
    Chris Blue29-Mar-07 19:09 
    QuestionHow to display the EVENT LOG MESSAGE TEXT? 1000 thanks for helping !!! Pin
    Chris Blue2-Mar-07 19:36
    Chris Blue2-Mar-07 19:36 
    AnswerRe: How to display the EVENT LOG MESSAGE TEXT? 1000 thanks for helping !!! Pin
    Chris Blue2-Mar-07 19:40
    Chris Blue2-Mar-07 19:40 
    GeneralThanks for the most excellent code! Pin
    William E. Thompson14-Feb-07 5:18
    William E. Thompson14-Feb-07 5:18 
    GeneralRe: Thanks for the most excellent code! Pin
    Christian Merritt14-Feb-07 5:32
    Christian Merritt14-Feb-07 5:32 
    GeneralUpdate to the code posted above. Pin
    William E. Thompson14-Feb-07 7:44
    William E. Thompson14-Feb-07 7:44 
    GeneralCOOL!!! Pin
    Nicola Costantini29-Sep-06 0:34
    Nicola Costantini29-Sep-06 0:34 
    just a little fix....

    private void StartWatch()
    {
    try
    {
    // if someone remove the Log on register...
    if (!EventLog.Exists(watchLog))
    watchLog = "Application";

    Great stuff!!
    Cheers
    Nicola
    GeneralRe: COOL!!! Pin
    Christian Merritt28-Jun-07 16:21
    Christian Merritt28-Jun-07 16:21 
    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 
    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 

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