• Type of event, i.e. simple, condition, or tracking.
• Event categories
• Lowest severity, i.e. all events with a severity greater than or equal to the specified severity.
• Highest severity, i.e. all events with a severity less than or equal to the specified severity.
• Process areas
• Event Sources
A list of values for a single criterion are logically ORed together (e.g. if two event categories arespecified, event notifications for both categories will be received). If multiple criteria are specified, they will be logically ANDed together, i.e. only those events satisfying all criteria will be selected. An example is specifying both lowest severity and highest severity will result in the selection of events with severities lying between the two values.
An OPCEventSubscription object has only one filter.
Syntax
| Visual Basic (Declaration) | |
|---|---|
Public Function SetFilter( _ ByVal EventType As Integer, _ ByVal EventCategories() As Integer, _ ByVal LowSeverity As Integer, _ ByVal HighSeverity As Integer, _ ByVal AreaList() As String, _ ByVal SourceList() As String _ ) As Integer | |
| C# | |
|---|---|
public int SetFilter( int EventType, int[] EventCategories, int LowSeverity, int HighSeverity, string[] AreaList, string[] SourceList ) | |
Parameters
- EventType
- A bit mask specifying which event types are of interest; OPC_SIMPLE_EVENT, OPC_CONDITION_EVENT, OPC_TRACKING_EVENT, OPC_ALL_EVENTS. These types can be OR’ed together to filter multiple types. A value of 0 is an error and E_INVALIDARG will be returned.
- EventCategories
- Array of event categories of interest. These are DWORD event category codes returned by QueryEventCategories. A pointer to a NULL DWORD must be passed if dwNumCategories is 0.
- LowSeverity
- Lowest severity of interest (inclusive). The severity range is 1 .. 1000.
- HighSeverity
- Highest severity of interest (inclusive). The severity range is 1 .. 1000.
- AreaList
- Array of process area strings of interest - only events or conditions in these areas will be reported. Area strings can be obtained using GetQualifiedAreaName. It is possible to specify areas using the wildcard syntax. Servers must support the wildcard syntax described in OPC AE specs Appendix A.
- SourceList
- Array of event sources of interest - only events from these sources will be reported. It is possible to specify sources using the wildcard syntax. Servers must support the wildcard syntax described in OPC AE specs Appendix A.