I use Arcgis runtime for net 100.2 and create C#/WPF application.

I developed custom circle (code of circle is) :

double slice = 2 * Math.PI / 360;

Esri.ArcGISRuntime.Geometry.PointCollection pcol = new Esri.ArcGISRuntime.Geometry.PointCollection();

Polyline polyline = new Polyline(points_Circle);

double radius = Convert.ToDouble(GeometryEngine.Length(polyline));

double sliceRadius = 0.07;

double radian = Math.Acos((radius - sliceRadius) / radius);

double angle = radian * (180 / Math.PI);

//Calcuate tendon

double tendon = radius * Math.Sin(angle);

if (tendon < 0.1)

{

tendon = 0.1;

angle = Math.Asin(0.1 /radius);

}

for (double i = 0; i <= 360; i += angle)

{

double rad = slice * i;

double px = points_Circle[0].X + radius * Math.Cos(rad);

double py = points_Circle[0].Y + radius * Math.Sin(rad);

pcol.Add(new MapPoint(px, py));

}

Polyline p = new Polyline(pcol);

// Create the graphic with polyline and symbol

Graphic graphicPoly = new Graphic(p, lineSymbol);

Image of circle is:

When intersect this circle with rectangle (code of rectangle is):

var rectangle = await MyMapView.SketchEditor.StartAsync(SketchCreationMode.Rectangle, false);

appear next message:

How to solved this problem?

I don't see you ever assigning a spatial reference to the geometries. Does the problem go away if you assign the correct spatial reference?