dymaptic.GeoBlazor.Core
dymaptic.GeoBlazor.Core.Components.Layers
FeatureLayer Class
A FeatureLayer is a single layer that can be created from a Map Service or Feature Service; ArcGIS Online or ArcGIS
Enterprise portal items; or from an array of client-side features. The layer can be either a spatial (has
geographic features) or non-spatial (table).
ArcGIS
JS API
</a>
public class FeatureLayer : dymaptic.GeoBlazor.Core.Components.Layers.Layer
Inheritance System.Object 🡒 Microsoft.AspNetCore.Components.ComponentBase 🡒 MapComponent 🡒 Layer 🡒 FeatureLayer
Example
Constructors
FeatureLayer() Constructor
Constructor for use as a razor component
public FeatureLayer();
FeatureLayer(string, PortalItem, IReadOnlyCollection, string[], string, Nullable, Nullable, string, Nullable, string, Nullable, Nullable, Nullable) Constructor
Constructor for creating a new FeatureLayer in code. Either the url, portalItem, or source parameter must be
specified.
public FeatureLayer(string? url=null, dymaptic.GeoBlazor.Core.Components.PortalItem? portalItem=null, System.Collections.Generic.IReadOnlyCollection<dymaptic.GeoBlazor.Core.Components.Layers.Graphic>? source=null, string[]? outFields=null, string? definitionExpression=null, System.Nullable<double> minScale=null, System.Nullable<double> maxScale=null, string? objectIdField=null, System.Nullable<dymaptic.GeoBlazor.Core.Components.Geometries.GeometryType> geometryType=null, string? title=null, System.Nullable<double> opacity=null, System.Nullable<bool> visible=null, System.Nullable<dymaptic.GeoBlazor.Core.Components.Layers.ListMode> listMode=null);
Parameters
url System.String
The absolute URL of the REST endpoint of the layer, non-spatial table or service
portalItem PortalItem
The PortalItem from which the layer is loaded.
source System.Collections.Generic.IReadOnlyCollection<Graphic>
A collection of Graphic objects used to create a FeatureLayer.
outFields System.String[]
An array of field names from the service to include with each feature.
definitionExpression System.String
The SQL where clause used to filter features on the client.
minScale System.Nullable<System.Double>
The minimum scale (most zoomed out) at which the layer is visible in the view.
maxScale System.Nullable<System.Double>
The maximum scale (most zoomed in) at which the layer is visible in the view.
objectIdField System.String
The name of an oidfield containing a unique value or identifier for each feature in the layer.
geometryType System.Nullable<GeometryType>
The geometry type of the feature layer. All features must be of the same type.
title System.String
The title of the layer used to identify it in places such as the Legend and LayerList widgets.
opacity System.Nullable<System.Double>
The opacity of the layer.
visible System.Nullable<System.Boolean>
Indicates if the layer is visible in the View. When false, the layer may still be added to a Map instance that is
referenced in a view, but its features will not be visible in the view.
listMode System.Nullable<ListMode>
Indicates how the layer should display in the LayerList widget. The possible values are listed below.
Properties
FeatureLayer.DefinitionExpression Property
The SQL where clause used to filter features on the client.
public string? DefinitionExpression { get; set; }
Property Value
FeatureLayer.Fields Property
An array of fields in the layer.
public System.Collections.Generic.IReadOnlyCollection<dymaptic.GeoBlazor.Core.Components.Layers.Field>? Fields { get; set; }
Property Value
System.Collections.Generic.IReadOnlyCollection<Field>
FeatureLayer.GeometryType Property
The geometry type of the feature layer. All features must be of the same type.
public System.Nullable<dymaptic.GeoBlazor.Core.Components.Geometries.GeometryType> GeometryType { get; set; }
Property Value
FeatureLayer.LabelingInfo Property
The label definition for this layer, specified as an array of Label.
public System.Collections.Generic.HashSet<dymaptic.GeoBlazor.Core.Components.Layers.Label>? LabelingInfo { get; set; }
Property Value
System.Collections.Generic.HashSet<Label>
FeatureLayer.LayerType Property
Used internally to identify the sub type of Layer
public override string LayerType { get; }
Property Value
FeatureLayer.MaxScale Property
The maximum scale (most zoomed in) at which the layer is visible in the view.
public System.Nullable<double> MaxScale { get; set; }
Property Value
System.Nullable<System.Double>
FeatureLayer.MinScale Property
The minimum scale (most zoomed out) at which the layer is visible in the view.
public System.Nullable<double> MinScale { get; set; }
Property Value
System.Nullable<System.Double>
FeatureLayer.ObjectIdField Property
The name of an oidfield containing a unique value or identifier for each feature in the layer.
public string? ObjectIdField { get; set; }
Property Value
FeatureLayer.OrderBy Property
Determines the order in which features are drawn in the view.
public System.Collections.Generic.HashSet<dymaptic.GeoBlazor.Core.Components.Layers.OrderedLayerOrderBy>? OrderBy { get; set; }
Property Value
System.Collections.Generic.HashSet<OrderedLayerOrderBy>
FeatureLayer.OutFields Property
An array of field names from the service to include with each feature.
public string[]? OutFields { get; set; }
Property Value
FeatureLayer.PopupTemplate Property
The PopupTemplate for the layer.
public dymaptic.GeoBlazor.Core.Components.Popups.PopupTemplate? PopupTemplate { get; set; }
Property Value
FeatureLayer.PortalItem Property
The PortalItem from which the layer is loaded.
public dymaptic.GeoBlazor.Core.Components.PortalItem? PortalItem { get; set; }
Property Value
FeatureLayer.Relationships Property
Array of relationships set up for the layer. Each object in the array describes the layer’s relationship with
another layer or table.
public dymaptic.GeoBlazor.Core.Objects.Relationship[]? Relationships { get; set; }
Property Value
FeatureLayer.Renderer Property
The Renderer assigned to the layer.
public dymaptic.GeoBlazor.Core.Components.Renderers.Renderer? Renderer { get; set; }
Property Value
FeatureLayer.Source Property
A collection of Graphic objects used to create a FeatureLayer.
public System.Collections.Generic.IReadOnlyCollection<dymaptic.GeoBlazor.Core.Components.Layers.Graphic>? Source { get; set; }
Property Value
System.Collections.Generic.IReadOnlyCollection<Graphic>
FeatureLayer.SpatialReference Property
The spatial reference for the feature layer
public dymaptic.GeoBlazor.Core.Components.Geometries.SpatialReference? SpatialReference { get; set; }
Property Value
FeatureLayer.Url Property
The absolute URL of the REST endpoint of the layer, non-spatial table or service
public string? Url { get; set; }
Property Value
Methods
FeatureLayer.Add(Field) Method
Add a field to the current layer’s source
public System.Threading.Tasks.Task Add(dymaptic.GeoBlazor.Core.Components.Layers.Field field);
Parameters
field Field
The field to add
Returns
FeatureLayer.Add(Graphic) Method
Add a graphic to the current layer’s source
public System.Threading.Tasks.Task Add(dymaptic.GeoBlazor.Core.Components.Layers.Graphic graphic);
Parameters
graphic Graphic
The graphic to add
Returns
FeatureLayer.Add(IEnumerable) Method
Adds a collection of graphics to the feature layer
public System.Threading.Tasks.Task Add(System.Collections.Generic.IEnumerable<dymaptic.GeoBlazor.Core.Components.Layers.Graphic> graphics);
Parameters
graphics System.Collections.Generic.IEnumerable<Graphic>
The graphics to add
Returns
FeatureLayer.CreatePopupTemplate(CreatePopupTemplateOptions) Method
Creates a popup template for the layer, populated with all the fields of the layer.
public System.Threading.Tasks.Task<dymaptic.GeoBlazor.Core.Components.Popups.PopupTemplate> CreatePopupTemplate(dymaptic.GeoBlazor.Core.Components.Layers.CreatePopupTemplateOptions? options=null);
Parameters
options CreatePopupTemplateOptions
Options for creating the popup template.
Returns
System.Threading.Tasks.Task<PopupTemplate>
FeatureLayer.CreateQuery() Method
Creates query parameter object that can be used to fetch features that satisfy the layer’s configurations such as
definitionExpression, gdbVersion, and historicMoment. It will return Z and M values based on the layer’s data
capabilities. It sets the query parameter’s outFields property to [“*”]. The results will include geometries of
features and values for all available fields for client-side queries or all fields in the layer for server side
queries.
public System.Threading.Tasks.Task<dymaptic.GeoBlazor.Core.Objects.Query> CreateQuery();
Returns
System.Threading.Tasks.Task<Query>
FeatureLayer.OnQueryFeaturesCreateChunk(string, int) Method
partial query result return for Blazor Server, to avoid SignalR size limits
public void OnQueryFeaturesCreateChunk(string chunk, int chunkIndex);
Parameters
chunk System.String
chunkIndex System.Int32
FeatureLayer.QueryExtent(Query, CancellationToken) Method
Executes a Query against the feature service and returns the Extent of features that satisfy the query. If no
parameters are specified, then the extent and count of all features satisfying the layer’s configuration/filters
are returned.
To query for the extent of features/graphics available to or visible in the View on the client rather than making a
server-side query, you must use the QueryExtent(Query, CancellationToken) method.
public System.Threading.Tasks.Task<dymaptic.GeoBlazor.Core.Components.Layers.ExtentQueryResult> QueryExtent(dymaptic.GeoBlazor.Core.Objects.Query? query=null, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query Query
Specifies the attributes and spatial filter of the query. If no parameters are specified, then the extent and count
of all features satisfying the layer’s configuration/filters are returned.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<ExtentQueryResult>
FeatureLayer.QueryFeatureCount(Query, CancellationToken) Method
Executes a Query against the feature service and returns the number of features that satisfy the query. If no
parameters are specified, the total number of features satisfying the layer’s configuration/filters is returned.
To query for the count of features/graphics available to or visible in the View on the client rather than making a
server-side query, you must use the QueryFeatureCount(Query, CancellationToken) method.
public System.Threading.Tasks.Task<int> QueryFeatureCount(dymaptic.GeoBlazor.Core.Objects.Query? query=null, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query Query
Specifies the attributes and spatial filter of the query. If no parameters are specified, the total number of
features satisfying the layer’s configuration/filters is returned.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<System.Int32>
FeatureLayer.QueryFeatures(Query, CancellationToken) Method
Executes a Query against the feature service and returns the number of features that satisfy the query. If no
parameters are specified, the total number of features satisfying the layer’s configuration/filters is returned.
To query for the count of features/graphics available to or visible in the View on the client rather than making a
server-side query, you must use the QueryFeatureCount(Query, CancellationToken) method.
public System.Threading.Tasks.Task<dymaptic.GeoBlazor.Core.Components.Layers.FeatureSet?> QueryFeatures(dymaptic.GeoBlazor.Core.Objects.Query? query=null, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query Query
Specifies the attributes and spatial filter of the query. If no parameters are specified, the total number of
features satisfying the layer’s configuration/filters is returned.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<FeatureSet>
FeatureLayer.QueryObjectIds(Query, CancellationToken) Method
Executes a Query against the feature service and returns an array of Object IDs for features that satisfy the input
query. If no parameters are specified, then the Object IDs of all features satisfying the layer’s
configuration/filters are returned.
To query for ObjectIDs of features/graphics available to or visible in the View on the client rather than making a
server-side query, you must use the QueryObjectIds(Query, CancellationToken) method.
public System.Threading.Tasks.Task<int[]> QueryObjectIds(dymaptic.GeoBlazor.Core.Objects.Query query, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query Query
Specifies the attributes and spatial filter of the query. If no parameters are specified, then the Object IDs of
all features satisfying the layer’s configuration/filters are returned.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<System.Int32[]>
FeatureLayer.QueryRelatedFeatures(RelationshipQuery, CancellationToken) Method
Executes a RelationshipQuery against the feature service and returns FeatureSets grouped by source layer or table
objectIds.
public System.Threading.Tasks.Task<System.Collections.Generic.Dictionary<int,dymaptic.GeoBlazor.Core.Components.Layers.FeatureSet?>?> QueryRelatedFeatures(dymaptic.GeoBlazor.Core.Objects.RelationshipQuery query, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query RelationshipQuery
Specifies relationship parameters for querying related features or records from a layer or a table.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<System.Collections.Generic.Dictionary<System.Int32,FeatureSet>>
FeatureLayer.QueryRelatedFeaturesCount(RelationshipQuery, CancellationToken) Method
Executes a RelationshipQuery against the feature service and when resolved, it returns an object containing key
value pairs. Key in this case is the objectId of the feature and value is the number of related features associated
with the feature.
public System.Threading.Tasks.Task<System.Collections.Generic.Dictionary<int,int>> QueryRelatedFeaturesCount(dymaptic.GeoBlazor.Core.Objects.RelationshipQuery query, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query RelationshipQuery
Specifies relationship parameters for querying related features or records from a layer or a table.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<System.Collections.Generic.Dictionary<System.Int32,System.Int32>>
FeatureLayer.QueryTopFeatureCount(TopFeaturesQuery, CancellationToken) Method
Executes a TopFeaturesQuery against a feature service and returns the count of features or records that satisfy the
query.
public System.Threading.Tasks.Task<int> QueryTopFeatureCount(dymaptic.GeoBlazor.Core.Objects.TopFeaturesQuery query, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query TopFeaturesQuery
Specifies the attributes, spatial, temporal, and top filter of the query. The topFilter parameter must be set.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<System.Int32>
Remarks
Known Limitations: Currently, the QueryTopFeatureCount(TopFeaturesQuery, CancellationToken) is only supported with server-side
FeatureLayers.
FeatureLayer.QueryTopFeatures(TopFeaturesQuery, CancellationToken) Method
Executes a TopFeaturesQuery against a feature service and returns a FeatureSet once the promise resolves. The
FeatureSet contains an array of top features grouped and ordered by specified fields. For example, you can call
this method to query top three counties grouped by state names while ordering them based on their populations in a
descending order.
public System.Threading.Tasks.Task<dymaptic.GeoBlazor.Core.Components.Layers.FeatureSet?> QueryTopFeatures(dymaptic.GeoBlazor.Core.Objects.TopFeaturesQuery query, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query TopFeaturesQuery
Specifies the attributes, spatial, temporal, and top filter of the query. The topFilter parameter must be set.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<FeatureSet>
Remarks
Known Limitations: Currently, the QueryTopFeatures(TopFeaturesQuery, CancellationToken) is only supported with server-side
FeatureLayers.
FeatureLayer.QueryTopFeaturesExtent(TopFeaturesQuery, CancellationToken) Method
Executes a TopFeaturesQuery against a feature service and returns the Extent of features that satisfy the query.
public System.Threading.Tasks.Task<dymaptic.GeoBlazor.Core.Components.Layers.ExtentQueryResult> QueryTopFeaturesExtent(dymaptic.GeoBlazor.Core.Objects.TopFeaturesQuery? query=null, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query TopFeaturesQuery
Specifies the attributes, spatial, temporal, and top filter of the query. The topFilter parameter must be set.
cancellationToken System.Threading.CancellationToken
A cancellation token that can be used to cancel the query operation.
Returns
System.Threading.Tasks.Task<ExtentQueryResult>
Remarks
Known Limitations: Currently, the QueryTopFeaturesExtent(TopFeaturesQuery, CancellationToken) is only supported with server-side
FeatureLayers.
FeatureLayer.QueryTopObjectIds(TopFeaturesQuery, CancellationToken) Method
public System.Threading.Tasks.Task<int[]> QueryTopObjectIds(dymaptic.GeoBlazor.Core.Objects.TopFeaturesQuery query, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
Parameters
query TopFeaturesQuery
cancellationToken System.Threading.CancellationToken
Returns
System.Threading.Tasks.Task<System.Int32[]>
FeatureLayer.RegisterChildComponent(MapComponent) Method
Called from dymaptic.GeoBlazor.Core.Components.MapComponent.OnAfterRenderAsync(System.Boolean) to “Register” the current component with it’s parent.
public override System.Threading.Tasks.Task RegisterChildComponent(dymaptic.GeoBlazor.Core.Components.MapComponent child);
Parameters
child MapComponent
The calling, child component to register
Returns
Exceptions
InvalidChildElementException
Throws if the current child is not a valid sub-component to the parent.
FeatureLayer.Remove(Field) Method
Remove a field from the current layer
public System.Threading.Tasks.Task Remove(dymaptic.GeoBlazor.Core.Components.Layers.Field field);
Parameters
field Field
The field to remove
Returns
FeatureLayer.Remove(Graphic) Method
Remove a graphic from the current layer
public System.Threading.Tasks.Task Remove(dymaptic.GeoBlazor.Core.Components.Layers.Graphic graphic);
Parameters
graphic Graphic
The graphic to remove
Returns
FeatureLayer.UnregisterChildComponent(MapComponent) Method
Undoes the “Registration” of a child with its parent.
public override System.Threading.Tasks.Task UnregisterChildComponent(dymaptic.GeoBlazor.Core.Components.MapComponent child);
Parameters
child MapComponent
The child to unregister
Returns
FeatureLayer.ValidateRequiredChildren() Method
When a MapView is prepared to render, this will check to make sure that all properties with the
RequiredPropertyAttribute are provided.
public override void ValidateRequiredChildren();
Exceptions
MissingRequiredChildElementException
The consumer needs to provide the missing child component
MissingRequiredOptionsChildElementException
The consumer needs to provide ONE of the options of child components