Class: QgsValueRelationFieldFormatter¶
-
class
qgis.core.
QgsValueRelationFieldFormatter
¶ Bases:
QgsFieldFormatter
Constructor for QgsValueRelationFieldFormatter.
QgsValueRelationFieldFormatter(
QgsValueRelationFieldFormatter
)Field formatter for a value relation field. A value relation field formatter looks up the values from features on another layer.
Methods
createCache(config: Dict[str, Any], formFeature:
QgsFeature
= QgsFeature()) -> List[QgsValueRelationFieldFormatter.ValueRelationItem] Create a cache for a value relation field.Returns a list of attributes required by the form context
expression
Returns a list of variables required by the form context
expression
Check whether the
feature
has all values required by theexpression
Check if the
expression
requires a form scope (i.e.- rtype
str
- param layer
Returns the (possibly NULL) layer from the widget’s
config
andproject
- param layer
Utility to convert a list or a string representation of an (hstore style: {1,2…}) list in
value
to a string list-
class
ValueRelationItem
(key: Any, value: str)¶ Bases:
sip.wrapper
Constructor for ValueRelationItem
QgsValueRelationFieldFormatter.ValueRelationItem() Constructor for ValueRelationItem
QgsValueRelationFieldFormatter.ValueRelationItem(QgsValueRelationFieldFormatter.ValueRelationItem)
- Parameters
key (Any) –
value (str) –
-
key
¶
-
value
¶
-
createCache
(self, layer: QgsVectorLayer, fieldIndex: int, config: Dict[str, Any]) → Any¶ createCache(config: Dict[str, Any], formFeature:
QgsFeature
= QgsFeature()) -> List[QgsValueRelationFieldFormatter.ValueRelationItem] Create a cache for a value relation field. This can be used to keep the value map in the local memory if doing multiple lookups in a loop.- Parameters
config (Dict[str) – The widget configuration
formFeature – The feature currently being edited with current attribute values
- Return type
Any
- Returns
A kvp list of values for the widget
New in version 3.0.
- Parameters
layer (QgsVectorLayer) –
fieldIndex (int) –
-
expressionFormAttributes
(expression: str) → Set[str]¶ Returns a list of attributes required by the form context
expression
- Parameters
expression (str) – Form filter expression
- Return type
Set[str]
- Returns
list of attributes required by the expression
New in version 3.2.
-
expressionFormVariables
(expression: str) → Set[str]¶ Returns a list of variables required by the form context
expression
- Parameters
expression (str) – Form filter expression
- Return type
Set[str]
- Returns
list of variables required by the expression
New in version 3.2.
-
expressionIsUsable
(expression: str, feature: QgsFeature) → bool¶ Check whether the
feature
has all values required by theexpression
- Return type
bool
- Returns
True
if the expression can be used
New in version 3.2.
- Parameters
expression (str) –
feature (QgsFeature) –
-
expressionRequiresFormScope
(expression: str) → bool¶ Check if the
expression
requires a form scope (i.e. if it uses fields or geometry of the currently edited feature).- Parameters
expression (str) – The widget’s filter expression
- Return type
bool
- Returns
True
if the expression requires a form scope
New in version 3.2.
-
id
(self) → str¶ - Return type
str
-
representValue
(self, layer: QgsVectorLayer, fieldIndex: int, config: Dict[str, Any], cache: Any, value: Any) → str¶ - Parameters
layer (QgsVectorLayer) –
fieldIndex (int) –
config (Dict[str) –
cache (Any) –
value (Any) –
- Return type
str
-
resolveLayer
(config: Dict[str, Any], project: QgsProject) → QgsVectorLayer¶ Returns the (possibly NULL) layer from the widget’s
config
andproject
New in version 3.8.
- Parameters
config (Dict[str) –
project (QgsProject) –
- Return type
-
sortValue
(self, layer: QgsVectorLayer, fieldIndex: int, config: Dict[str, Any], cache: Any, value: Any) → Any¶ - Parameters
layer (QgsVectorLayer) –
fieldIndex (int) –
config (Dict[str) –
cache (Any) –
value (Any) –
- Return type
Any
-
valueToStringList
(value: Any) → List[str]¶ Utility to convert a list or a string representation of an (hstore style: {1,2…}) list in
value
to a string listNew in version 3.2.
- Parameters
value (Any) –
- Return type
List[str]