QgsProcessingParameterField class

A vector layer or feature source field parameter for processing algorithms.

Reference

Base classes

class QgsProcessingParameterDefinition: Base class for the definition of processing parameters.

Public types

enum DataType { Any = -1, Numeric = 0, String = 1, DateTime = 2 }: Field data types.

Public static functions

static auto fromScriptCode(const QString& name, const QString& description, bool isOptional, const QString& definition) -> QgsProcessingParameterField*: Creates a new parameter using the definition from a script code.
static auto typeName() -> QString: Returns the type name for the parameter class.

Constructors, destructors, conversion operators

QgsProcessingParameterField(const QString& name, const QString& description = QString(), const QVariant& defaultValue = QVariant(), const QString& parentLayerParameterName = QString(), DataType type = Any, bool allowMultiple = false, bool optional = false): Constructor for QgsProcessingParameterField.

Public functions

auto allowMultiple() const -> bool: Returns whether multiple field selections are permitted.
auto asScriptCode() const -> QString override: Returns the parameter definition encoded in a string which can be used within a Python processing script.
auto checkValueIsAcceptable(const QVariant& input, QgsProcessingContext* context = nullptr) const -> bool override: Checks whether the specified input value is acceptable for the parameter.
auto clone() const -> QgsProcessingParameterDefinition* override: Creates a clone of the parameter definition.
auto dataType() const -> DataType: Returns the acceptable data type for the field.
auto dependsOnOtherParameters() const -> QStringList override: Returns a list of other parameter names on which this parameter is dependent (e.g.
auto fromVariantMap(const QVariantMap& map) -> bool override: Restores this parameter to a QVariantMap.
auto parentLayerParameterName() const -> QString: Returns the name of the parent layer parameter, or an empty string if this is not set.
void setAllowMultiple(bool allowMultiple): Sets whether multiple field selections are permitted.
void setDataType(DataType type): Sets the acceptable data type for the field.
void setParentLayerParameterName(const QString& parentLayerParameterName): Sets the name of the parent layer parameter.
auto toVariantMap() const -> QVariantMap override: Saves this parameter to a QVariantMap.
auto type() const -> QString override: Unique parameter type name.
auto valueAsPythonString(const QVariant& value, QgsProcessingContext& context) const -> QString override: Returns a string version of the parameter input value, which is suitable for use as an input parameter value when running an algorithm directly from a Python command.

Enum documentation

enum QgsProcessingParameterField::DataType

Field data types.

Enumerators
Any	Accepts any field.
Numeric	Accepts numeric fields.
String	Accepts string fields.
DateTime	Accepts datetime fields.

Function documentation

bool QgsProcessingParameterField::allowMultiple() const

Returns whether multiple field selections are permitted.

bool QgsProcessingParameterField::checkValueIsAcceptable(const QVariant& input, QgsProcessingContext* context = nullptr) const override

Checks whether the specified input value is acceptable for the parameter.

Returns true if the value can be accepted. The optional context parameter can be specified to allow a more stringent check to be performed, capable of checking for the presence of required layers and other factors within the context.

DataType QgsProcessingParameterField::dataType() const

Returns the acceptable data type for the field.

QStringList QgsProcessingParameterField::dependsOnOtherParameters() const override

Returns a list of other parameter names on which this parameter is dependent (e.g.

field parameters which depend on a parent layer parameter).

bool QgsProcessingParameterField::fromVariantMap(const QVariantMap& map) override

Restores this parameter to a QVariantMap.

Subclasses should ensure that they call the base class method.

QString QgsProcessingParameterField::parentLayerParameterName() const

Returns the name of the parent layer parameter, or an empty string if this is not set.

void QgsProcessingParameterField::setAllowMultiple(bool allowMultiple)

Sets whether multiple field selections are permitted.

void QgsProcessingParameterField::setDataType(DataType type)

Sets the acceptable data type for the field.

void QgsProcessingParameterField::setParentLayerParameterName(const QString& parentLayerParameterName)

Sets the name of the parent layer parameter.

Use an empty string if this is not required.

QVariantMap QgsProcessingParameterField::toVariantMap() const override

Saves this parameter to a QVariantMap.

Subclasses should ensure that they call the base class method and then extend the result with additional properties.

QString QgsProcessingParameterField::valueAsPythonString(const QVariant& value, QgsProcessingContext& context) const override

Returns a string version of the parameter input value, which is suitable for use as an input parameter value when running an algorithm directly from a Python command.

The returned value must be correctly escaped - e.g. string values must be wrapped in ' 's.