"Geometry cannot have Z values" exception in ArcGIS Engine

Question

I'm trying to put a list of point features (selected points) into a new FeatureClass. but when I add them to my FeatureClass I get the "Geometry cannot have Z values." exception on the line "buff.Shape = point;" . can any one help?

        List<IFeature> features = GetSelectedFeatures(axMapControl1.get_Layer(0) as IFeatureLayer);
        IPointArray pa = new PointArrayClass();

        List<IPoint> p = new List<IPoint>();
        for (int i = 0; i < features.Count; i++)
        {
            p.Add(features[i].ShapeCopy as IPoint);
            pa.Add(p[i]);
        }


        IPoint point = new PointClass();
        point = pa.get_Element(0);


        point.SpatialReference = p[0].SpatialReference;

        IWorkspaceFactory workspaceFactory = new ShapefileWorkspaceFactoryClass();
        IWorkspace workspace = workspaceFactory.OpenFromFile(@"C:\", 0);
        IFeatureWorkspace featureWorkspace = workspace as IFeatureWorkspace;

        IFeatureClass FC = CreateFeatureClass("FC", featureWorkspace, pa.get_Element(0).SpatialReference,esriGeometryType.esriGeometryPoint);

        IFeatureCursor fCur = FC.Insert(false);
        IFeatureBuffer buff = FC.CreateFeatureBuffer();


        buff.Shape = point;
        fCur.InsertFeature(buff);


        fCur.Flush();
        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(fCur);

        IFeatureLayer fl = new ESRI.ArcGIS.Carto.FeatureLayer();
        fl.FeatureClass = FC;
        var layer = fl as ILayer;

        axMapControl1.AddLayer(layer);

        axMapControl1.Refresh();

Answer 1

I just encountered a similar problem and wanted to offer an answer since Richard Morgan's above comment solved the problem.

I had a point feature class that was not Z-enabled but was, at the same time, rejecting the assignment of a new point geometry that had no Z value. The error message was "Geometry cannot have Z values". It was confusing simply because there were no Z values, anywhere.This new point geometry even had "NaN" as the value of the Z property.

I took Richard's advice and QI'd to IZAware:

IPoint toPoint = new PointClass(); IZAware toZAware = toPoint as IZAware; toZAware.ZAware = false;

Then I assigned the XY value and spatial reference of the new point.

(toZAware as IPoint).SpatialReference = spatialRef;
(toZAware as IPoint).X = serviceLine.ToPoint.X;
(toZAware as IPoint).Y = serviceLine.ToPoint.Y;

After this, I was allowed to assign and store the new point geometry to the Shape field of my feature.