View active alarms in user defined ListView

The following example shows how to create a user defined List View in Visual Basic for the TcEventLogger, that shows active events.

Do following steps to create the sample:

1. Create a standard EXE project with a form.
2. Add MS Standard Controls 6 to the Control list.
3. Add the Beckhoff TcEventLogger Library to the references.
4. Add the List View ActiveX Control to the form.
5. Rename the List View to lvwAlarm
6. Copy following Code to the form:

Option Explicit
Dim WithEvents objEventLogger As TcEventLog

'------------------------------------------------------
' this method is called when the form is loaded
'
Private Sub Form_Load()
  Set objEventLogger = New TcEventLog
  Call initListView
  Call DisplayActiveAlarms
End Sub

'------------------------------------------------------
' this method is called when a new alarm is issued
'
Private Sub objEventLogger_OnNewEvent(ByVal evtObj As Object)
  ' cast to TcEvent interface
  Dim objEvent As TcEvent
  Set objEvent = evtObj
  ' get the key
  Dim newKey As String
  newKey = GetKeyFromIDs(objEvent.SrcId, objEvent.Id)
  'get the Event Message Text
  Dim strMessage As String
  strMessage = objEvent.GetMsgString(1033)
  'add the Message to the listview
  Dim objListItem As ListItem
  Set objListItem = lvwAlarm.ListItems.Add(, newKey, strMessage & objEvent.Date)
End Sub

'------------------------------------------------------
' this method is called when a alarm is reset
'
Private Sub objEventLogger_OnResetEvent(ByVal evtObj As Object)
  ' cast to TcEvent interface
  Dim objEvent As TcEvent
  Set objEvent = evtObj
  ' get the key
  Dim newKey As String
  newKey = GetKeyFromIDs(objEvent.SrcId, objEvent.Id)
  'remove the event from the listview
  Call lvwAlarm.ListItems.Remove(newKey)
End Sub

'------------------------------------------------------
' initalize the list view
'
Sub initListView()
  lvwAlarm.View = lvwReport
  lvwAlarm.GridLines = True
  'init the Header
  Dim objColHdr As ColumnHeaders
  Set objColHdr = lvwAlarm.ColumnHeaders
  Debug.Assert Not objColHdr Is Nothing
  Call objColHdr.Clear
  Call objColHdr.Add(1, "Message", "Message", 5000)
End Sub

'------------------------------------------------------
' display all active alarms
'
Private Sub DisplayActiveAlarms()
 'clear the listview
 Call lvwAlarm.ListItems.Clear

 Debug.Assert Not objEventLogger Is Nothing

 Dim objEvent As TcEvent
 'get the number of active Events
 For Each objEvent In objEventLogger.EnumActiveEventsEx
  If (Not objEvent Is Nothing) Then
   'here we get one Event from the collection
   Dim strMessage As String
   'get the Event Message Text
   strMessage = objEvent.GetMsgString(1033)
   'get the key
   Dim newKey As String
   newKey = GetKeyFromIDs(objEvent.SrcId, objEvent.Id)
   'add the Message to the listview
   Dim objListItem As ListItem
   Set objListItem = lvwAlarm.ListItems.Add(, newKey, strMessage & objEvent.Date)
  End If
 Next
End Sub

'------------------------------------------------------
' create unique key from event group and event id
'
Public Function GetKeyFromIDs(ByVal SourceId As Long, ByVal EventId As Long) As String
  GetKeyFromIDs = SourceId & "-" & EventId
End Function

The List View has a column with the Event message. The Method DisplayActiveAlarms gets the active alarms from the EventLogger and shows them. When a new Event is shown or a actual event is reset the OnNewEvent event-function adds events to the List View and the OnResetEvent event-function removes events from the List View. The method GetKeyFromIDs created a key of the event group and the event id.

The user defined Event View only supports events that are not quit-requiring. To use it for quit-requiring events you have to add functions for ITcEventLogEvents::OnSignalEvent and ITcEventLogEvents::OnConfirmEvent.