Capture the Entry of Items into the Event Log (VB.NET)

Category:

C#, VB.NET, ASP.NET

Type:

Snippets

Difficulty:

Beginning

Author:

m.posseth

Version Compatibility: Visual Basic.NET

More information:

This code demonstrates how to capture the entry of items in the event log in a running vb application. The code in the sub that is invoked by the entry is designed as a trivial example, you have to substitute your own business logic.

Instructions: Copy the declarations and code below and paste directly into your VB project.

Declarations:
Private WithEvents myAppLog As EventLog Private WithEvents mySysLog As EventLog

Code:

'THE MAIN CODE
Public Sub InitializeEventLogCapture()
        myAppLog = New EventLog()
        myAppLog.Log = "Application"
        myAppLog.EnableRaisingEvents = True
        mySysLog = New EventLog()
        mySysLog.Log = "System"
        mySysLog.EnableRaisingEvents = True
        AddHandler myAppLog.EntryWritten, AddressOf EntryWritten
        AddHandler mySysLog.EntryWritten, AddressOf EntryWritten
    End Sub

'CHANGE THE SUB BASED ON YOUR OWN NEEDS
    Private Sub EntryWritten(ByVal sender As Object, ByVal e As System.Diagnostics.EntryWrittenEventArgs)
        Dim sType As String
        Select Case e.Entry.EntryType

Case EventLogEntryType.Information
                sType = "Information"
            Case EventLogEntryType.Error
                sType = "Error"
            Case EventLogEntryType.Error
                sType = "Warning"
        End Select

MsgBox(e.Entry.Message & "(" & sType & ")")

End Sub

'DEMO: TO ILLUSTRATE THAT IT WORKS

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        InitializeEventLogCapture()
        WriteToEventLog("this is a test")
    End Sub
    Public Function WriteToEventLog(ByVal Entry As String, _
       Optional ByVal AppName As String = "VB.NET Application", _
       Optional ByVal EventType As _
       EventLogEntryType = EventLogEntryType.Information, _
       Optional ByVal LogName As String = "Application") As Boolean

'*************************************************************
        'PURPOSE: Write Entry to Event Log using VB.NET
        'PARAMETERS: Entry - Value to Write
        '            AppName - Name of Client Application. Needed 
        '              because before writing to event log, you must 
        '              have a named EventLog source. 
        '            EventType - Entry Type, from EventLogEntryType 
        '              Structure e.g., EventLogEntryType.Warning, 
        '              EventLogEntryType.Error
        '            LogName: Name of Log (System, Application; 
        '              Security is read-only) If you 
        '              specify a non-existent log, the log will be
        '              created

'RETURNS:   True if successful, false if not

'EXAMPLES: 
        '1. Simple Example, Accepting All Defaults
        '    WriteToEventLog "Hello Event Log"

'2.  Specify EventSource, EventType, and LogName
        '    WriteToEventLog("Danger, Danger, Danger", "MyVbApp", _
        '                      EventLogEntryType.Warning, "System")
        '
        'NOTE:     EventSources are tightly tied to their log. 
        '          So don't use the same source name for different 
        '          logs, and vice versa
        '******************************************************

Dim objEventLog As New EventLog()

Try
            'Register the App as an Event Source
            If Not objEventLog.SourceExists(AppName) Then

objEventLog.CreateEventSource(AppName, LogName)
            End If

objEventLog.Source = AppName

'WriteEntry is overloaded; this is one
            'of 10 ways to call it
            objEventLog.WriteEntry(Entry, EventType)
            Return True
        Catch Ex As Exception
            Return False

End Try

End Function