Query an ArcGisDynamicMapServiceLayer

[DanielBachmann1]

Hi,

I created an ArcGisDynamicMapServiceLayer on a local map service and opened a shapefile. Is it possible to query the attributes of this layer? I set a DefinitionExpression through DynamicLayerInfo but how can I access the attributes of the visible features?

Using a QueryTask always results in 0 features, I used the blocking and non blocking methods. Are querys on local services not allowed?

kind regards,

Daniel

[LucasDanzinger]

A QueryTask should work just fine. If you print out the URL to your local service once it starts, you should be able to see it in the browser, and execute a query from there as well. Are you making sure to point the url to the individual layer, and not the root of the service?

[DanielBachmann1]

In order to add the shapefile to the local service, I created an mpk-File "blank.mpk" with ArcMap which includes only an empty Polyline-Shapefile. As shown in the examples, I added the shapefile to the associated ArcGisDynamicMapServiceLayer (after modifying the dynamic workspaces) like this

EsriRuntimeQt::SimpleRenderer* simpleRenderer;

simpleRenderer = new EsriRuntimeQt::SimpleRenderer(EsriRuntimeQt::SimpleLineSymbol(QColor(0, 100, 250), 3.0), this);
EsriRuntimeQt::DrawingInfo* drawingInfo = new EsriRuntimeQt::DrawingInfo(simpleRenderer, 20, this);
layerInfo->setDrawingInfo(drawingInfo);

// Create the table data source

EsriRuntimeQt::TableDataSource* dataSource = new EsriRuntimeQt::TableDataSource(this);
dataSource->setWorkspaceId(m_workspaceId);
dataSource->setDataSourceName(m_dataSourceFileName);

// Set the data source

EsriRuntimeQt::LayerDataSource* layerDataSource = new EsriRuntimeQt::LayerDataSource(this);
layerDataSource->setDataSource(dataSource);
layerInfo->setLayerSource(layerDataSource);
layerInfo->setDefinitionExpression(m_queryString);
m_dynamicLocalServiceLayer2->refresh();

After this the Polylines from the shapefile are drawn, but the url shows the old attributes of the "blank.mpk"! A query on that empty package will always return zero results...

[DanielBachmann1]

Just tried a QueryTask with tha data of the shapefile in an mpk-File and it works, so I'll be missing something!?

Queried the shapefile using gdal-api for now (bit ugly) but it seams to work...

[LucasDanzinger]

One more thing to try. In your Query object (that you will pass into the Query Task), can you try calling setDynamicLayerInfo (ArcGIS Runtime SDK for Qt C++ API: EsriRuntimeQt::Query Class Reference)). Then, pass in a DynamicLayerInfo created from your LayerSource.

[DanielBachmann1]

Used the code below, but again only the empty layer in the mpk-File is queried not the one loaded from the shapefile. If queried for the field "id" set->count() is 0. A query for a field which is only defined in the shapefile restults in (set == NULL).

EsriRuntimeQt::Query query;

query.setWhere("id >= 0");

query.setDynamicLayerInfo(layerInfo);

m_queryTask = new EsriRuntimeQt::QueryTask(m_dynamicLocalServiceLayer2->url()+"/0",this);

EsriRuntimeQt::FeatureSet* set = m_queryTask->executeAndWait(query);

if ( set )

{

     qDebug()<<set->count();

}

[LucasDanzinger]

Can you try setting your where clause to "1=1" to see if you can get anything/everything back?

[DanielBachmann1]

Query "1=1" returns no results, which means (set != 0), but (set->count() == 0). Which is only correct for the "empty" mpk-File before adding the shapefile dynamically.

[DanielBachmann1]

Hi Luke,

Found some time to make a minimal example using only files from the sdk samples. Maybe this will leads to new insights 🙂

kr,

Daniel