' Ensure that the source has already been registered using
' EventLogInstaller or EventLog.CreateEventSource.
Dim sourceName as String = "SampleApplicationSource"
If EventLog.SourceExists(sourceName)
    
    ' Define an informational event with no category.
    ' The message identifier corresponds to the message text in the
    ' message resource file defined for the source.
    Dim myEvent As EventInstance = New EventInstance(UpdateCycleCompleteMsgId, 0)
    ' Write the event to the event log using the registered source.
    EventLog.WriteEvent(sourceName, myEvent)

    ' Reuse the event data instance for another event entry.
    ' Set the entry category and message identifiers for
    ' the appropriate resource identifiers in the resource files
    ' for the registered source.  Set the event type to Warning.

    myEvent.CategoryId = RefreshCategoryMsgId
    myEvent.EntryType = EventLogEntryType.Warning
    myEvent.InstanceId = ServerConnectionDownMsgId

    ' Write the event to the event log using the registered source.
    ' Insert the machine name into the event message text.
    EventLog.WriteEvent(sourceName, myEvent, Environment.MachineName)

Else 
    Console.WriteLine("Warning - event source {0} not registered", _
        sourceName)
End If

Dim sourceName As String = "SampleApplicationSource"

           ' Create the event source if it does not exist.
           If Not EventLog.SourceExists(sourceName)
  
               ' Call a local method to register the event log source
               ' for the event log "myNewLog."  Use the resource file
               ' EventLogMsgs.dll in the current directory for message text.

               Dim messageFile As String =  String.Format("{0}\\{1}", _
                   System.Environment.CurrentDirectory, _
                   "EventLogMsgs.dll")

               CreateEventSourceSample1(messageFile)
           End If 

           ' Get the event log corresponding to the existing source.
           Dim myLogName As String = EventLog.LogNameFromSourceName(sourceName,".")
       
           Dim myEventLog As EventLog = new EventLog(myLogName, ".", sourceName)

           ' Define two audit events.
           Dim myAuditSuccessEvent As EventInstance = new EventInstance(AuditSuccessMsgId, 0, EventLogEntryType.SuccessAudit)
           Dim myAuditFailEvent As EventInstance = new EventInstance(AuditFailedMsgId, 0, EventLogEntryType.FailureAudit)

           ' Insert the method name into the event log message.
           Dim insertStrings() As String = {"EventLogSamples.WriteEventSample1"}
           
           ' Write the events to the event log.

           myEventLog.WriteEvent(myAuditSuccessEvent, insertStrings)

           ' Append binary data to the audit failure event entry.
           Dim binaryData() As Byte = { 7, 8, 9, 10 }
           myEventLog.WriteEvent(myAuditFailEvent, binaryData, insertStrings)