Limits which dynamic entities are returned from an ArcGIS stream service. More...
| Import Statement: | import Esri.ArcGISRuntime |
| Since: | Esri.ArcGISRuntime 200.1 |
| Inherits: |
- List of all members, including inherited members
- ArcGISStreamServiceFilter is part of QML Type List.
Properties
- geometry : Geometry
- outFields : list<string>
- outSpatialReference : SpatialReference
- whereClause : string
Signals
Detailed Description
Set ArcGISStreamService::filter to an object of this type to apply a server-side filter on observations streamed from an ArcGIS stream service. Spatial or attribute filters (or both) are supported.
Using this server-side filter is useful for limiting how much data is streamed from an ArcGISStreamService and handled in the client application, which can help with application performance and memory efficiency.
Property Documentation
geometry : Geometry |
The geometry that is used to filter results.
Dynamic entities that intersect this geometry are included in the notification. Entities outside of this geometry are excluded.
The default value is null, meaning no spatial filter is applied to the stream.
Currently, only Enums.GeometryTypeEnvelope geometries are supported.
[since Esri.ArcGISRuntime 200.2] outFields : list<string> |
A collection of field names that identify the observation values the server should return. This property instructs the service to return a subset of values when pushing observations to the client. Restricting the values returned will limit the amount of memory required to store individual observations and therefore reduce the memory footprint of the application.
The default is an empty QStringList, which returns all observation fields from the server.
The output fields take effect when connecting to an empty DynamicEntityDataSource. The following three steps are required to modify the output fields for an existing connection: DynamicEntityDataSource::disconnectDataSource, DynamicEntityDataSource::purgeAll, and DynamicEntityDataSource::connectDataSource.
Note that the geometry, track ID (if available), and timestamp fields are always included with each observation.
This property was introduced in Esri.ArcGISRuntime 200.2.
outSpatialReference : SpatialReference |
The spatial reference that dynamic entities are returned in.
Use this property to instruct the service to provide observation geometries in the given spatial reference.
This property is useful if the client application needs dynamic entities in a specific spatial reference. Setting this property forces the server to reproject geometries before adding observations to the stream. This relieves the client application from the performance burden of reprojecting dynamic entities.
The default value is null, meaning observation geometries should be returned in the spatial reference of the service.
whereClause : string |
A SQL expression that defines the dynamic entities to return.
Use this property to filter dynamic entities by attribute value. Setting this property forces the server to filter observations using the given expression before adding them to the stream.
The expression used as the whereClause should follow standard SQL syntax as discussed in the document SQL reference for query expressions used in ArcGIS.
The default value is an empty string, meaning that no attribute filter will be applied to the stream.
Signal Documentation
geometryChanged() |
Emitted when the geometry property changes.
Note: The corresponding handler is onGeometryChanged.
outSpatialReferenceChanged() |
Emitted when the outSpatialReference property changes.
Note: The corresponding handler is onOutSpatialReferenceChanged.
whereClauseChanged() |
Emitted when the whereClause property changes.
Note: The corresponding handler is onWhereClauseChanged.