class QOpcUaElementOperand#

Synopsis#

Methods#

def __init__()
def index()
def __ne__()
def setIndex()

Note

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Detailed Description#

The ElementOperand is defined in OPC UA 1.05 part 4, 7.7.4.2. It is used to identify another element in the filter by its index (the first element has the index 0).

This is required to create complex filters, for example to reference the two operands of the AND operation in ((Severity > 500) AND (Message == “TestString”)). The first step is to create content filter elements for the two conditions (Severity > 500) and (Message == “TestString”). A third content filter element is required to create an AND combination of the two conditions. It consists of the AND operator and two element operands with the indices of the two conditions created before:

QOpcUaMonitoringParameters::EventFilter filter;
...
// setup select clauses
...
QOpcUaContentFilterElement condition1;
QOpcUaContentFilterElement condition2;
QOpcUaContentFilterElement condition3;
condition1 << QOpcUaContentFilterElement::FilterOperator::GreaterThan << QOpcUaSimpleAttributeOperand("Severity") <<
                QOpcUaLiteralOperand(quint16(500), QOpcUa::Types::UInt16);
condition2 << QOpcUaContentFilterElement::FilterOperator::Equals << QOpcUaSimpleAttributeOperand("Message") <<
                QOpcUaLiteralOperand("TestString", QOpcUa::Types::String);
condition3 << QOpcUaContentFilterElement::FilterOperator::And << QOpcUaElementOperand(0) << QOpcUaElementOperand(1);
filter << condition1 << condition2 << condition3;

__init__()#

Default constructs an element operand with no parameters set.

__init__(arg__1)

Parameters:: arg__1 – QOpcUaElementOperand

Constructs an element operand from rhs.

__init__(index)

Parameters:: index – int

Constructs an element operand with index index.

index()#

Return type:: int

Returns the index of the filter element that is going to be used as operand.

See also

setIndex()

__ne__(rhs)#

Parameters:: rhs – QOpcUaElementOperand
Return type:: bool

Returns true if lhs a different value than rhs.

setIndex(index)#

Parameters:: index – int

Sets the index of the filter element that is going to be used as operand to index.

See also

index()