A free (open source) log monitor / log viewer for a multitude of data sources.
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logview4net is a log viewer.

It can monitor files, directories, incomming UDP/TCP traffic, the EventLog, SQL tables, Atom and RSS feeds.

logview4net needs the .Net 4.5.2 Runtime to execute.


  • Listens to a UDP port either in broadcast or single endpoint mode.
  • Monitors an eventlog, uses events on the local machine and polling on remote machines.
  • Monitors a log file or folder. Doing a tail using polling.
  • Monitors a table in a MS SQL-Server database. Doing a tail using polling.
  • Monitors RSS and Atom feeds. Strips most of HTML formatting from content.
  • Listens to a TCP port.
  • Monitors StdOut/StdErr of external application.
  • Can highlight or hide messages depending on content.
  • Supports multiple simultaneous listeners in each session.
  • Supports several simultaneous sessions (MDI).

File hashes

  • Sha256 hash of installer: 89 b5 fb a6 90 41 f8 92 f5 87 03 77 48 51 8e 65 1a c9 1b 1e b4 5b 51 c6 2f 8a e5 32 66 48 92 ab
  • Sha256 hash of logview4net.exe: b7 e5 55 8b c5 bd 92 5b 85 6d 29 bd 31 15 67 5c 0d 70 20 ce b1 db 0a 45 05 05 a7 bc 77 43 72 5a

To calculate the hash yourself in Windows execute the following: certutil -hashfile logview4net.exe sha256


  • The viewer configurator is not loaded with the right settings



  • Change .Net version to 4.5.2
  • Fix: An exception when loading configurations from file.


  • Fix Bug: #33 Log window is not displayed
  • Rewrote build pipeline in Python
  • Using Nuget to get the correct verson of MySql.Data
  • Fix: The button to restart a listener went out of sight


  • The main form now saves and restores its size and position.


  • Fix: Encoding problems in the RssListener
  • The installer is now signed with a verified certificate by Johan Idstam.


  • Fix: Multi line messages printed application class names instead of the actual content
  • Fix: Change of session title will now show in a running session


You can now drag/drop a file or folder into any textbox when configuring a listener to get the name of the dropped object.


  • Removed a binary component, a launcher, that wasn't doing anything useful.
  • Fixed bug in the rolling file storage that stopped polling listeners from running when there were more than one new line/message.


Small performance improvement in SqlListener and MySqlListener.


  • Added option to save all events to a rolling log file
  • Added an option to the viewer to skip the listener headers for messages. Only Tcp and Udp was affected.
  • Fixed bug: Not saving all config data for UserActions
  • Fixed request: An option to remove white space surrounding messages.


  • Added timestamp to MsSqlListener, MySqlListener and EventLogListener
  • Fixed some resizing when adding listeners to a session.


  • Added a user action that will execute any bat,cmd or exe when a pattern is found.
  • Added timestamp to UdpListener, FileListener, FolderListener, RssListener, StdOutListener, TcpListner and UdpListener. Using the date format documented here: http://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx


  • Added labels to the load/save button in the configure window
  • Added save to file context menu in the viewer window
  • Added match case and match word options to search dialog.


  • Fixed: [3467144] Filter displayed events (but do not ignore or remove them). Added an action that will filter out messages. Added a button in the toolbar to show all hidden messages. Added items in the pop up menu for a viewer to show hidden messages per action.
  • Fixed: Added MySql.data.dll to the install folder
  • Fixed: [3467137][2250823] The default font is "Courier new". But when one opens the font dialog then "Microsoft Sans Serif" is selected.
  • Fixed: [3467141] The Back color of the viewer is not take into account for user interaction/action configuration (text Example)


  • Fixed a bug where the text viewer ignored the 'Cache on pause' configuration option


  • Fixed a bug in MSSQL-Listener. The first row in a table was ignored if the user unchecked 'Start at end'
  • Added a MySQL listener kindly contributed by Balzás Botond


  • Fixed: [3048596] logview4net keeps redrawing view, even though it is Paused
  • Fixed: [2865511] F11 vill now hide/show the menu and the form border.
  • Fixed: An exception was sometimes thrown when closing a session window because the listener was not closed before the view.
  • Changed: The string pattern for an action is now a regular expression, not only an exact match.
  • Fixed: [3094649] tables list not retrieved when db name contains a period
  • Fixed: [2833781] HighlightMatch highlighting is offset by -1


  • Made the seach dialog to be not modal.
  • Added a 'Find Last' button to the search dialog.


  • Fixed: [2833781] HighLightMatch was of by one character


  • Fixed: [2793393] Added remote IP-address to the messages of the TCP-listener
  • Fixed: [2791880] Experimental TCP-listener. Please test it.
  • Fixed: [2777698] option to NOT display file data for FolderListener. The filename was not displayed when a file was changed.


  • Fixed: [2777698] option to NOT display file data for FolderListener


  • Fixed: [2770750] Text Foreground Color does not save correctly.
  • Fixed: [2770729] Settings Dont Stay


  • Fixed: [2250820] The part "User Interactions" in the settings dialog doesn't expand if one adds more patterns.
  • Fixed: [2250843] Manage actions missing scrollbar
  • Fixed: [2250810] FolderListener: logview4net crashes if an additional file ...
  • Fixed: Http authentication in the RSSListener
  • Fixed: [2250834] Save dialog default folder
  • Fixed: [2250823] The default font is "Courier new". But when one opens the font dialog then"Microsoft Sans Serif" is selected.


  • Fixed: The config dialog is not shown when the user has started with a preselected config file and chooses 'New Session'
  • Fixed [2250817]: Minimize button on settings dialog removed.
  • Fixed [2250852]: Message when checking for updates
  • Fixed [2250830]: FileListener path name in config


  • Changed some code in the Highlighting code that fixed the 'of by some characters' coloring bug.
  • Fixed the vertical alignment of label texts in listener configurators.
  • Added basic authentication for the rss listener
  • Shows the initial items in reverse order for the rss listener.(Will probably add an option for this instead.)
  • Changed the caption on the rss poll interval label. The interval is minutes not milliseconds.
  • Forced poll interval on rss listener to be one or more.


  • The listeners prefixes are now part of the caption in the session config window. This is so that the prefixes are visible even though the configurator is minimized.
  • Fixed [1876190]:Added some sleep to the file listener.


  • Added search dialog to text viewer. Reached by CTRL + F or right click.


  • The amount of memory used for the text buffer is now managed by the application. If there are any listeners with 'old' data. (Like a file listener where you load all the data and not only tailing it.) It will truncate the data to ½GB when it reaches 1GB. If there are only tailing listeners then it will truncate the data at 10MB to 5MB.
  • Changed license to Artistic License 2.0


  • Fixed: The progressbar was hidden after the first large file.
  • Request:Show show short filename on prefix-filename
  • Fixed: It is not possible to change the buffersize in the viewer config window.
  • Fixed: HighlightMatch only formatted the first occurance of the pattern in a message.
  • Fixed: The textbox reverts to default format when enforcing the buffer size
  • Added a Play Sound action that will play a PCM Wave File on pattern match.


  • Made it a lot faster to load existing data in files and SQL-tables.


  • The setting to add a filename to the prefix in the folder listener was lost in an earlier release.


  • Fixed: Actions where lost when fontsize had decimals.
  • Fixed: Create a new assembly for the listeners that are Microsoft Specific (EventLog and SQL-server for now)
  • Fixed for all but the MSListeners: Make all listener configurators use the new dynamic style and move them to non visual assembly.


  • Added option to choose encoding in Udp-listener


  • Fixed: Add an IgnoreBlock action that should have an IgnoreStart + IgnoreEnd pattern
  • Fixed: Make it possible to ingore events on pause instead of caching them.
  • Fixed: Make the cmd-line parser use the StdOut-listener for .exe-files
  • Enabled the StdOut listener
  • Fixed a dispose bug on all listeners.


  • Added some command line configuration. Documented in the help file.
  • Made it possible to associate the .l4n extension with logview4net


  • Fixed: [1711956] When changing Poll timeout, settings not saved


  • RssListener moved to core.
  • StdOutListener moved to core (needs some more testing to go live)
  • FolderListener moved to core.
  • Fixed: The buttons in the config-form moves out of range when there are lots of listeners
  • Fixed & Handled: SecuritExceptions in EventLogListener on Vista There is now a manifetst embedded that elevates the application then it starts. I have also added some error handling to fail a bit nicer on most exceptions in the EventlogListener
  • Fixed: [1698479] When loading configuration, actions are lost Trying to parse font size as int
  • Added security elevation to the manifest file to make the app run with admin rights in Vista.
  • FileListener moved to core.
  • UdpListener moved to core.
  • Fixed: Make the installer know about .NET 2.0
  • Fixed bug when the program tried to look for updates and had no connection.


  • Fixed the bug when loading a configuration of a UdpListener
  • Done: Add check for updates, check only once a week (6 to 9 days)
  • UdpListener uses dynamic configurator.
  • Added a folder listener.
  • Moved tests to its own assembly
  • Moved Session to core assembly
  • Moved Logger to core assembly
  • Fixed: Configuration of session didn't work with the new look.
  • Fixed: Help - Documentation crashed the application if help.htm was deleted
  • Fixed: Add listener with no selected listener crashed the app


  • Fixed: Removing listeners from the session configuration window didn't remove them from the session.


  • New version numbering Since the version number don't really mean much I'll start using year.week instead. If (however unlikely) I make two releases the same week I'll add a .number also.
  • Fixed: 'Add' button in ActionConfigurator miss aligned when there were no actions.
  • Fixed: Disable all context menu items in the viewer when nothing is selected.
  • Done: Give Load/Save buttons on configure form icons instead of text
  • Done: Create a new ConfigureSession form.
  • Done: Load logger settings from app.config
  • Fixed: Add an icon or text to the font button on action configurators
  • Fixed: The 'only tail' option doesn't work for feeds
  • Done: Add a contect-menu to the text viewer that allows for fast creation of actions.
  • Fixed: Make the RssListener publish only 'new' feed items.
  • Done: Accept filenames to monitor as command line arguments. (.exe-files will use the new stdOut-listener all other the old file-listener)
  • Fixed: Make the RssListener handle Atom
  • Fixed: Action configuration wasn't properly updated when changing format on existing action.
  • Fixed: Now the font information from the actions is applied in the viewer.
  • Done: Changed the ActionConfigurator Removed colorpicker Added button to configure font (including color)
  • Fixed: Sort actions on Pattern + Action priority (Ignore, HighlightMatch, HighLight, PopUp)
  • Done: New Action - HighlightMatch - Changes color (and font) on a matchin string inside an event.
  • Done: Execute multiple actions.
  • Done: New listener - RssListener, will monitor an rss feed (2.0, 0.92, Atom tested).


  • I messed up the version number a bit. The released 1.2 has all from the 1.1 Changelog.


  • Festure request 1489611: Scroll all windows
  • Moved project from CVS to Subversion on SourceForge (060317)
  • Changed default file extension for loading/saving configurations to *.xml
  • Added a toolbar button to toggle word wrap in the current viewer.
  • Changed the toolbar icons to use Silk Icons from: http://www.famfamfam.com/lab/icons/silk/
  • Actions can now be moved up & down in the action manager.


  • Fixed: Actions doesn't appear when configuring a running session.
  • Fixed:Headers missing in ActionManager when there are no actions.
  • Fixed:Values are not updated in listener configurators when loading settings from file.
  • Fixed: The ForeColor was not saved correctly when saving session configuration to file.


  • Allows some changes to listeners in a running session.
  • Allows changes to all parameters of a viewer in a running session.
  • Now is can Save/Load the configuration file
  • Fixed bug: Listeners to a runnig session wasn't started.
  • Fixed (sort of): Changes to the viewer in the Session Configurator isn't reverted when pressing 'Cancel' (Removed the Cancel button)


  • Fixed bug that prevented the use of EventLogListener.


  • Uses .NET 2.0
  • Uses MDI Windows instead of tabs.
  • Added a MS SQL-Server listener
  • Lots of internal changes.


  • Fixed bug when removing a listener in the config form.


  • Removed some Acions and implemented the PopUp Action.
  • Fixed the internals of configuring a session
  • Fixed a threading issue with multiple listeners
  • Fixed saving the configuration
  • Added functionality for all the buttons in the main toolbar


  • Fixed the session configuration dialog.