HOWTO: Clear the Windows NT Event Log in Visual Basic

• Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 32-bit only, for Windows, version 4.0
• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0

SUMMARY

Event logging in Windows provides a standard, centralized way for Windows and applications to record important software and hardware events. Event logging also supplies a standard user interface for viewing the logs and a programming interface for examining the logs.

This article illustrates how to clear the Windows NT Event Log with Visual Basic version 4.0 (32-bit) and later. This can be done using the ClearEventLog API call. While Visual Basic 5.0 and later versions have built in functionality for event logging, they do not provide the clearing functionality that the Win32 API does.

MORE INFORMATION

Although the parameter lpBackupFileName of ClearEvent is set to VbNullString, this can be set to a backup filename as well making a separate call to BackupEventLog unnecessary.

The following example illustrates how to clear the local Application Event Log.

Step by Step Example

1. Create a project with a Visual Basic form (named Form1) and a command button named cmdClearEventLog.



2. Add the following code to the Form1 code window:




Private Declare Function ClearEventLog Lib "advapi32.dll" Alias "ClearEventLogA" ( _
    ByVal hEventLog As Long, _
    ByVal lpBackupFileName As String) _
    As Long

Private Declare Function CloseEventLog Lib "advapi32.dll" ( _
    ByVal hEventLog As Long) _
    As Long

Private Declare Function OpenEventLog Lib "advapi32.dll" Alias "OpenEventLogA" ( _
    ByVal lpUNCServerName As String, _
    ByVal lpSourceName As String) _
    As Long

Private Sub cmdClearEventLog_Click()
    Dim hEventLog As Long
    Dim lretv As Long
    
    hEventLog = OpenEventLog(vbNullString, "Application")
    If hEventLog = 0 Then
         Debug.Print "OpenEventLog Failed"
         Exit Sub
    End If
    
    lretv = ClearEventLog(hEventLog, vbNullString)
    If lretv = 0 Then
         Debug.Print "ClearEventLog Failed"
         Exit Sub
    End If
                
    lretv = CloseEventLog(hEventLog)
    If lretv = 0 Then
         Debug.Print "CloseEventLog Failed"
         Exit Sub
    End If

End Sub 

3. Press F5 to run the project, and then the click cmdClearEventLog command button. If you check the Event log, it should be clear.

REFERENCES

For additional information on event logging from Visual Basic, click the article numbers below to view the articles in the Microsoft Knowledge Base:

Q154576 HOWTO: Write to the Windows NT Event Log from Visual Basic

Q161306 INFO: App.LogEvent Only Logs in Compiled Applications

Q184747 INFO: Event Logging in Visual Basic

Q216146 HOWTO: Get the Number of Windows NT Event Log Records in Visual Basic

Q216089 HOWTO: Backup the NT Event Log in Visual Basic

Additional query words:

Keywords : kbAPI kbEventLog kbNTOS kbSDKWin32 kbVBp kbVBp400 kbVBp500 kbVBp600 kbGrpVB kbDSupport kbCodeSnippet
Version : WINDOWS:4.0,5.0,6.0
Platform : WINDOWS
Issue type : kbhowto