The OPC UA ContentFilterElement. 更多...
import 语句: | import QtOpcUa. |
Since: | QtOpcUa 5.13 |
A content filter element contains an operator and operands. There are four different operator types which contain literal values, references to attributes of nodes or to other content filter elements.
A combination of one or more content filter elements makes a content filter which is used by the server to filter data for the criteria defined by the content filter elements. For example, the
where
clause of an event filter is a content filter which is used to decide if a notification is generated for an event.
QtOpcUa.FilterElement { operator: QtOpcUa.FilterElement.GreaterThanOrEqual firstOperand: QtOpcUa.SimpleAttributeOperand { ... } secondOperand: QtOpcUa.LiteralOperand { ... } }
另请参阅 EventFilter .
firstOperand : variant |
First operand to be used with the operator. This can be one of SimplateAttributeOperand, AttributeOperand , LiteralOperal or ElementOperand .
The filter operator.
secondOperand : variant |
Second operand to be used with the operator. This can be one of SimplateAttributeOperand, AttributeOperand , LiteralOperal or ElementOperand .