Syntax
| Visual Basic (Usage) |  Copy Code |
|---|---|
Dim instance As Session Dim nodesToRead As IList(Of HistoryReadValueId) Dim details As ReadRawModifiedDetails Dim callback As AsyncCallback Dim userData As Object Dim value As IAsyncResult value = instance.BeginHistoryReadRaw(nodesToRead, details, callback, userData) | |
| C# | |
|---|---|
public IAsyncResult BeginHistoryReadRaw( IList<HistoryReadValueId> nodesToRead, ReadRawModifiedDetails details, AsyncCallback callback, object userData ) | |
Parameters
- nodesToRead
- List of variable nodes to read data history from. Includes a continuation point to continue previous read requests.
- details
- Configuration parameters for the history read of raw data. Configuration parameters include - The start time of the requested time interval - The end time of the requested time interval - Setting whether bounding values should be returned - Limitation of the number of results per node
- callback
- The callback to use when the async call completes.
- userData
- The user data that is passed to the callback.
Return Value
An object which must be passed to the EndHistoryReadRaw method.Remarks
This method is used to read raw historical values of one or more
nodes in an ordered sequence for the defined time domain. Continuation
points are used to continue the read of the ordered sequence if not
all data can be returned in one read. The returned number can be
limited by the client or the server.
See #ReleaseHistoryContinuationPoints for cleaning up resources in
the server if read should not be continued with the returned
continuation point.
Requirements
Target Platforms: Windows 7/8/10, Windows Server 2003/2008/2012/2015, .NET4.x