Method IdentifyLayerAsync

IdentifyLayerAsync(Layer, Point, Double, Boolean)

Initiates an identify operation on the specified layer which will return the single visible topmost geolement only.

Declaration

public Task<IdentifyLayerResult> IdentifyLayerAsync(Layer layer, Point screenPoint, double tolerance, bool returnPopupsOnly)

Parameters

Type	Name	Description
Layer	layer	The layer in which to identify the geoelements.
Microsoft.Maui.Graphics.Point	screenPoint	The screen coordinates to identify the geoelements.
System.Double	tolerance	A radius in device-independent pixels (DIP) that specifies how precise the identify operation should be.
System.Boolean	returnPopupsOnly	true includes only popups in the identify results. An error is returned if the layer does not have popups. false includes both geoelements and popups in the identify results.

Returns

Type	Description
System.Threading.Tasks.Task<IdentifyLayerResult>	A task that represents the asynchronous identify operation on the specified layer. The value of the TResult parameter contains IdentifyLayerResult

Remarks

As locations from user gestures are not always accurate to the exact pixel, you can define a tolerance for the identify operation. The tolerance parameter sets the radius of a circle, centered at the specified coordinates, in device-independent pixels (DIP). If the tolerance value is 0, identify performs the test at the specified coordinates. If it is greater than 0, identify tests inside the circle. For touch displays a value of 22 is recommended to cover an average finger tap. The maximum allowed value is 100 DIPs.

The result is returned in a single IdentifyLayerResult instance. If the returnPopupsOnly parameter is true only Popups is populated. If the layer does not have popups an error is returned. If the returnPopupsOnly parameter is false, both GeoElements and Popups are populated, if the layer has popups.

Exceptions

Type	Condition
System.ArgumentNullException	layer

Applies to

Platforms and versions

Target	Versions
.NET	200.0 - 200.6
.NET Windows	200.0 - 200.6
.NET Android	200.3 - 200.6
.NET iOS	200.0 - 200.6

IdentifyLayerAsync(Layer, Point, Double, Boolean, CancellationToken)

Initiates an identify operation on the specified layer which will return the single visible topmost geolement only.

Declaration

public Task<IdentifyLayerResult> IdentifyLayerAsync(Layer layer, Point screenPoint, double tolerance, bool returnPopupsOnly, CancellationToken cancellationToken)

Parameters

Type	Name	Description
Layer	layer	The layer on which to run the identify.
Microsoft.Maui.Graphics.Point	screenPoint	The location at which to run identify in screen coordinates.
System.Double	tolerance	The width and height in screen coordinates of the square centered on screen coordinate that will be used in the identify.
System.Boolean	returnPopupsOnly	true includes only popups in the identify results. An error is returned if the layer does not have popups. false includes both geoelements and popups in the identify results.
System.Threading.CancellationToken	cancellationToken	A cancellation token that can be used by other objects or threads to receive notice of cancellation.

Returns

Type	Description
System.Threading.Tasks.Task<IdentifyLayerResult>	A task that represents the asynchronous identify operation on the specified layer. The value of the TResult parameter contains IdentifyLayerResult

Remarks

As locations from user gestures are not always accurate to the exact pixel, you can define a tolerance for the identify operation. The tolerance parameter sets the radius of a circle, centered at the specified coordinates, in device-independent pixels (DIP). If the tolerance value is 0, identify performs the test at the specified coordinates. If it is greater than 0, identify tests inside the circle. For touch displays a value of 22 is recommended to cover an average finger tap. The maximum allowed value is 100 DIPs.

The result is returned in a single IdentifyLayerResult instance. If the returnPopupsOnly parameter is true only Popups is populated. If the layer does not have popups an error is returned. If the returnPopupsOnly parameter is false, both GeoElements and Popups are populated, if the layer has popups.

Exceptions

Type	Condition
System.ArgumentNullException	layer

Applies to

Platforms and versions

Target	Versions
.NET	200.0 - 200.6
.NET Windows	200.0 - 200.6
.NET Android	200.3 - 200.6
.NET iOS	200.0 - 200.6

IdentifyLayerAsync(Layer, Point, Double, Boolean, Int64)

Identifies a limited number of geoelements in the specified layer or sublayer, at the given screen point.

Declaration

public Task<IdentifyLayerResult> IdentifyLayerAsync(Layer layer, Point screenPoint, double tolerance, bool returnPopupsOnly, long maximumResults)

Parameters

Type	Name	Description
Layer	layer	The layer in which to identify the geoelements.
Microsoft.Maui.Graphics.Point	screenPoint	The screen coordinates to identify the geoelements.
System.Double	tolerance	A radius in device-independent pixels (DIP) that specifies how precise the identify operation should be.
System.Boolean	returnPopupsOnly	true includes only popups in the identify results. An error is returned if the layer does not have popups. false includes both geoelements and popups in the identify results.
System.Int64	maximumResults	The maximum number of geoelements and/or popups returned in the IdentifyLayerResult. A value of -1 indicates unlimited results.

Returns

Type	Description
System.Threading.Tasks.Task<IdentifyLayerResult>	A task that represents the asynchronous identify operation on the specified layer. The value of the TResult parameter contains IdentifyLayerResult

Remarks

As locations from user gestures are not always accurate to the exact pixel, you can define a tolerance for the identify operation. The tolerance parameter sets the radius of a circle, centered at the specified coordinates, in device-independent pixels (DIP). If the tolerance value is 0, identify performs the test at the specified coordinates. If it is greater than 0, identify tests inside the circle. For touch displays a value of 22 is recommended to cover an average finger tap. The maximum allowed value is 100 DIPs.

The result is returned in a single IdentifyLayerResult instance. If the returnPopupsOnly parameter is true only Popups is populated. If the layer does not have popups an error is returned. If the returnPopupsOnly parameter is false, both GeoElements and Popups are populated, if the layer has popups. GeoElements and Popups provide the results in a top-to-bottom order.

Exceptions

Type	Condition
System.ArgumentNullException	layer

Applies to

Platforms and versions

Target	Versions
.NET	200.0 - 200.6
.NET Windows	200.0 - 200.6
.NET Android	200.3 - 200.6
.NET iOS	200.0 - 200.6

IdentifyLayerAsync(Layer, Point, Double, Boolean, Int64, CancellationToken)

Initiates an identify operation on the specified layer.

Declaration

public Task<IdentifyLayerResult> IdentifyLayerAsync(Layer layer, Point screenPoint, double tolerance, bool returnPopupsOnly, long maximumResults, CancellationToken cancellationToken)

Parameters

Type	Name	Description
Layer	layer	The layer on which to run the identify.
Microsoft.Maui.Graphics.Point	screenPoint	The location at which to run identify in screen coordinates.
System.Double	tolerance	The width and height in screen coordinates of the square centered on screen coordinate that will be used in the identify.
System.Boolean	returnPopupsOnly	true includes only popups in the identify results. An error is returned if the layer does not have popups. false includes both geoelements and popups in the identify results.
System.Int64	maximumResults	The maximum size of the result set of geoelements.
System.Threading.CancellationToken	cancellationToken	A cancellation token that can be used by other objects or threads to receive notice of cancellation.

Returns

Type	Description
System.Threading.Tasks.Task<IdentifyLayerResult>	A task that represents the asynchronous identify operation on the specified layer. The value of the TResult parameter contains IdentifyLayerResult

Remarks

As locations from user gestures are not always accurate to the exact pixel, you can define a tolerance for the identify operation. The tolerance parameter sets the radius of a circle, centered at the specified coordinates, in device-independent pixels (DIP). If the tolerance value is 0, identify performs the test at the specified coordinates. If it is greater than 0, identify tests inside the circle. For touch displays a value of 22 is recommended to cover an average finger tap. The maximum allowed value is 100 DIPs.

The result is returned in a single IdentifyLayerResult instance. If the returnPopupsOnly parameter is true only Popups is populated. If the layer does not have popups an error is returned. If the returnPopupsOnly parameter is false, both GeoElements and Popups are populated, if the layer has popups. GeoElements and Popups provide the results in a top-to-bottom order.

Exceptions

Type	Condition
System.ArgumentNullException	layer

Applies to

Platforms and versions

Target	Versions
.NET	200.0 - 200.6
.NET Windows	200.0 - 200.6
.NET Android	200.3 - 200.6
.NET iOS	200.0 - 200.6