topic Re: Label by attribute in ArcGIS Pro SDK Questions

Label by attribute

Daniel4 — Wed, 21 Dec 2022 13:40:28 GMT

Hi Everbody

I am trying to label a FeatureLayer with values from an attribute, but somehow it fails. I have calculated the z-value and want to label that, but for some reason it label another attribute.

In the CIMLabelClass I define the Expression to be the 'zValue' attribute:

var labelFeatureLayer = new CIMLabelClass { Name = "labelFeatureLayer", ExpressionEngine = LabelExpressionEngine.Arcade, Expression = "$feature.zValue", TextSymbol = SymbolFactory.Instance.ConstructTextSymbol().MakeSymbolReference(), Visibility = true }; var lyrDefn = fcLayer.GetDefinition() as CIMFeatureLayer; var listLabelClasses = lyrDefn.LabelClasses.ToList(); listLabelClasses.Add(labelFeatureLayer); lyrDefn.LabelClasses = listLabelClasses.ToArray(); fcLayer.SetDefinition(lyrDefn); fcLayer.SetLabelVisibility(true);

But its just showing a different attribute (in this case its the objectid)

Re: Label by attribute

GKmieliauskas — Wed, 21 Dec 2022 14:42:00 GMT

Hi,

I think you need to switch off visibility for other existing label classes. Look at Esri community sample LabelLineFeatures

//Turn off all the label classes except this one foreach (var lc in listLabelClasses) { lc.Visibility = lc.Name == "labelFeatureLayer" ? true : false; }

Re: Label by attribute

Wolf — Thu, 22 Dec 2022 05:49:59 GMT

The following snippet worked for me:

protected override async void OnClick() { var fcLayer = MapView.Active.Map.GetLayersAsFlattenedList().OfType<FeatureLayer>().Where(fl => fl.Name == "TestPoints").FirstOrDefault(); await QueuedTask.Run(() => { List<CIMLabelClass> newLabels = new List<CIMLabelClass>() { new CIMLabelClass { Name = "labelFeatureLayer", ExpressionEngine = LabelExpressionEngine.Arcade, Expression = "Geometry($feature).z", TextSymbol = SymbolFactory.Instance.ConstructTextSymbol().MakeSymbolReference(), Visibility = true } }; var lyrDefn = fcLayer.GetDefinition() as CIMFeatureLayer; lyrDefn.LabelClasses = newLabels.ToArray(); fcLayer.SetDefinition(lyrDefn); fcLayer.SetLabelVisibility(true); }); }

@GKmieliauskas is correct as there can be multiple labels with visibility. The snippet above removes all but the new label from the array of labels.

Re: Label by attribute

Daniel4 — Mon, 02 Jan 2023 12:06:38 GMT

Hi, thanks.

I tried with your code @Wolf but ArcGIS Pro doesn't show the label.

The label tab dont show the new label class:

But if I manual in ArcGis Pro create a label class (eg. 'test'), suddenly the new label class appires:

Do I need to delete some Label Classes before? Or do I need do to something with 'Class 1'?