'DeclarationPublic Sub PerformPoll()
'UsageDim instance As EasySparkplugEdgeNodeCore instance.PerformPoll()
public void PerformPoll()
public: void PerformPoll();
| Exception | Description |
|---|---|
| System.InvalidOperationException | A method call was invalid for the object's current state. This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception. |
| System.ObjectDisposedException | An operation was performed on a disposed object. |
This method first raises the ISparkplugProducerEvents.Poll event (in the implementations, this is usually done through calling the virtual OnPoll method).
If the event is handled (its System.ComponentModel.HandledEventArgs.Handled property is set to true), your code is expected to collect the data for publishing itself, providing the whole payload at once, in the event result (OpcLabs.EasySparkplug.OperationModel.SparkplugProducerPollEventArgs.Result). The component will then send the payload out (if there is anything to publish), by internally calling the PublishDataPayload method. The individual metrics will not be polled (read) by the component.
If the event is not handled (its System.ComponentModel.HandledEventArgs.Handled property remains at false), the component will poll (read) the individual metrics, and then publish the data that has changed. This is done in following steps:
This method is meant for invocation from your code when PublishingInterval equals to System.Threading.Timeout.Infinite, and the polling is therefore not done periodically by the producer.
The producer must be started, otherwise System.InvalidOperationException is thrown.
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