Reference

IOpcEventHistoryProvider Members

Type

IOpcEventHistoryProvider

Namespace

Opc.UaFx.Server

Assembly

Opc.UaFx.Advanced.dll

Package

Opc.UaFx.Advanced v2.59.0

Properties

Node

Gets the OpcObjectNode for which this instance provides event history data.

OpcObjectNode Node { get; }

ReadOnly Property Node As OpcObjectNode

Property value

OpcObjectNode

An instance of the OpcObjectNode class this provider is responsible for.

Methods

ReadEventHistory

Retrieves a sequence of OpcEvent instances representing the historical events for the associated Node according to the query parameters specified.

IEnumerable<OpcEvent> ReadEventHistory(
    OpcContext context,
    OpcEventFilter filter,
    DateTime? startTime,
    DateTime? endTime,
    bool timeFlowsBackward,
    uint? maxCount)

Function ReadEventHistory(
    context As OpcContext,
    filter As OpcEventFilter,
    startTime As Date?,
    endTime As Date?,
    timeFlowsBackward As Boolean,
    maxCount As UInteger?) As IEnumerable(Of OpcEvent)

Parameters

Name	Type	Description
context	OpcContext	The OpcContext of the requesting session.
filter	OpcEventFilter	The OpcEventFilter to use to filter the event history, including the select-clause and where-clause. The server does not apply the WhereClause — the implementation must evaluate it, e.g. by translating it into a database query.
startTime	Nullable<DateTime>	The inclusive start of the requested time range, or null if no lower bound is specified.
endTime	Nullable<DateTime>	The exclusive end of the requested time range, or null if no upper bound is specified. Exception: when startTime equals endTime, the single event at that exact timestamp is returned (i.e. endTime becomes inclusive).
timeFlowsBackward	Boolean	The value true if results should be returned in reverse chronological order.
maxCount	Nullable<UInt32>	The maximum number of events to return, or null for no limit.

Returns

IEnumerable<OpcEvent>

The matching OpcEvent instances. Use Create to reconstruct events from stored field values.