Zoom to query result from data grid

[KarenEllett]

I have a query task that then populates a datagrid with the results.  I'd like to be able to zoom to a particular feature when it's clicked on in the datagrid using the SelectionChanged event; I have it working with the results from a FindTask, using the findresult, but I can't quite figure out how to make it work with QueryTask and FeatureSet.  Can anyone help?  I've included the code below for the FindTask code, but I haven't been able to correctly alter it to work for the Query results.

        private void FindResults_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            // Highlight the graphic feature associated with the selected row
            DataGrid dataGrid = sender as DataGrid;

            int selectedIndex = dataGrid.SelectedIndex;
            if (selectedIndex > -1)
            {
                FindResult findResult = (FindResult)resultsDataGrid.SelectedItem;
                Graphic graphic = findResult.Feature;
                ESRI.ArcGIS.Client.Geometry.Envelope selectedFeatureExtent = findResult.Feature.Geometry.Extent;

                ESRI.ArcGIS.Client.Geometry.Envelope displayExtent = new ESRI.ArcGIS.Client.Geometry.Envelope(
                selectedFeatureExtent.XMin - 500,
                selectedFeatureExtent.YMin - 500,
                selectedFeatureExtent.XMax + 500,
                selectedFeatureExtent.YMax + 500);

                MapApplication.Current.Map.ZoomTo(displayExtent);

                string StrGeometry = findResult.Feature.Geometry.GetType().ToString();

                if (StrGeometry.Equals("ESRI.ArcGIS.Client.Geometry.MapPoint"))
                {
                    graphic.Symbol = Circle;
                }

                if (StrGeometry.Equals("ESRI.ArcGIS.Client.Geometry.Polygon"))
                {
                    graphic.Symbol = Fill;
                }

                if (StrGeometry.Equals("ESRI.ArcGIS.Client.Geometry.Polyline"))
                {
                    graphic.Symbol = YellowLine;
                }


                GraphicsLayer graphicsLayer = MapApplication.Current.Map.Layers["MyGraphicsLayer"] as GraphicsLayer;
                graphicsLayer.ClearGraphics();

                graphicsLayer.Graphics.Add(graphic);

            }




        }