How to set ClassBreakRenderer on GraphicsOvelay

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08-25-2019 08:55 PM
MaraStoica2
New Contributor II

I'm trying to create a ClassBreakRenderer and set it on a GraphicsOvelay and cannot get it to work. The renderer works fine on a FeatureLayer, but doesn't work on a GraphicsOverlay that's been created using the same data as the FeatureLayer. I'm not sure what I'm missing here. Is there a sample somewhere that shows how to do this? I pasted the code below, and also attached the repro case, in case someone is up for giving me a hand in getting to the bottom of this. Working with 100.5. Thank you!!!

- Mara

private async void RenderData()
{
	// Create a new map based on the streets base map.
	Map newMap = new Map(Basemap.CreateStreets());

	// Create an envelope that covers the continental US in the web Mercator spatial reference.
	Envelope continentalUSEnvelope = new Envelope(-14193469.5655232, 2509617.28647268, -7228772.04749191, 6737139.97573925, SpatialReferences.WebMercator);

	// Zoom the map to the extent of the envelope.
	newMap.InitialViewpoint = new Viewpoint(continentalUSEnvelope);

	// Assign the map to the MapView.
	MyMapView.Map = newMap;
	MyMapView.GraphicsOverlays.Add(new GraphicsOverlay());

	// CHANGE THIS FLAG TO SWITCH TEST BETWEEN FEATURE LAYER AND GRAPHICS OVERLAY
	var useFeatureLayer = true;

	if (useFeatureLayer)
	{
		// set feature layer and renderer and add it to the map
		var featureLayer = new FeatureLayer(new Uri("https://services8.arcgis.com/KsXZDThvSinzJ3pq/arcgis/rest/services/test_pipeline/FeatureServer/0"));
		featureLayer.Renderer = CreateClassBreaksRenderer();
		MyMapView.Map.OperationalLayers.Add(featureLayer);
	}
	else
	{
		// set feature table and query it to retrieve all features
		var featTable = new ServiceFeatureTable(new Uri("https://services8.arcgis.com/KsXZDThvSinzJ3pq/arcgis/rest/services/test_pipeline/FeatureServer/0"));
		var queryParams = new QueryParameters { WhereClause = "1=1" };
		var featureResult = await featTable.QueryFeaturesAsync(queryParams, QueryFeatureFields.LoadAll);

		// create graphics from the features and add them to the map in a graphics overlay
		foreach (var result in featureResult)
		{
			var pipeSegment = result.Geometry;
			var graphic = new Graphic(pipeSegment);
			graphic.Attributes.Add("break", result.Attributes["break"]);
			MyMapView.GraphicsOverlays[0].Graphics.Add(new Graphic(pipeSegment));
		}

		// create and set renderer for the graphics overlay
		MyMapView.GraphicsOverlays[0].Renderer = CreateClassBreaksRenderer();
	}
}

private ClassBreaksRenderer CreateClassBreaksRenderer()
{
	// Create symbols
	var symbol1 = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Red, 7);
	var symbol2 = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Yellow, 7);
	var symbol3 = new SimpleLineSymbol(SimpleLineSymbolStyle.Solid, Color.Green, 7);

	// Create class breaks
	List<ClassBreak> listClassBreaks = new List<ClassBreak>
	{
		new ClassBreak("1", "1", 0, 1, symbol1),
		new ClassBreak("2", "2", 1, 2, symbol2),
		new ClassBreak("3", "3", 2, 3, symbol3),
	};

	// Create and return the a class break renderer for use with the "break" field
	return new ClassBreaksRenderer("break", listClassBreaks);
}
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1 Solution

Accepted Solutions
dotMorten_esri
Esri Frequent Contributor

Looks like you're adding the wrong graphic (a new instance that doesn't have that attribute set)

Change

   MyMapView.GraphicsOverlays[0].Graphics.Add(new Graphic(pipeSegment));

to

   MyMapView.GraphicsOverlays[0].Graphics.Add(graphic);

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3 Replies
KimberlyMcCarty
Esri Contributor

The DefaultSymbol for the ClassBreaksRenderer seems to be working fine when it is set. I believe the class breaks symbology not applying may be more an issue with the renderer not being able to reach the graphic's attributes but we'll need to test it further.

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dotMorten_esri
Esri Frequent Contributor

Looks like you're adding the wrong graphic (a new instance that doesn't have that attribute set)

Change

   MyMapView.GraphicsOverlays[0].Graphics.Add(new Graphic(pipeSegment));

to

   MyMapView.GraphicsOverlays[0].Graphics.Add(graphic);

MaraStoica2
New Contributor II

I was afraid it was something silly like that. Thanks Morten!

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