How to zoom and flash geometry in ArcObjects?

Question

I'm developing arcgis add-in tools. I now want the map display to zoom to the geometry and then flash it.

I did this by defining two methods:

 public static void ZoomToGeometry(IGeometry geometry, IActiveView activeView)
    {
        IEnvelope env = geometry.Envelope;
        IGeometry5 geo = geometry as IGeometry5;

        if (env.Width == 0 || env.Height == 0)
        {
            IPoint centerPoint = new PointClass();
            centerPoint.X = geo.CentroidEx.X;
            centerPoint.Y = geo.CentroidEx.Y;

            //IDisplayTransformation displayTrans = activeView.ScreenDisplay.DisplayTransformation;
            //displayTrans.SpatialReference = activeView.FocusMap.SpatialReference;

            env.XMin = centerPoint.X - 0.001;
            env.XMax = centerPoint.X + 0.001;
            env.YMin = centerPoint.Y - 0.001;
            env.YMax = centerPoint.Y + 0.001;

            env.CenterAt(centerPoint);
        }
        env.Expand(0.5, 0.5, true);
        activeView.Extent = env;
        activeView.Refresh();
    }

and the flash geometry function borrowed from arcgis snippets:

public static void FlashGeometry(IGeometry geometry, IRgbColor color, IDisplay display, System.Int32 delay)
    {
        if (geometry == null || color == null || display == null)
        {
            return;
        }

        display.StartDrawing(display.hDC, (System.Int16)esriScreenCache.esriNoScreenCache); // Explicit Cast

        switch (geometry.GeometryType)
        {
            case esriGeometryType.esriGeometryPolygon:
                {
                    //Set the flash geometry's symbol.
                    ISimpleFillSymbol simpleFillSymbol = new SimpleFillSymbolClass();
                    simpleFillSymbol.Color = color;
                    ISymbol symbol = simpleFillSymbol as ISymbol; // Dynamic Cast
                    symbol.ROP2 = esriRasterOpCode.esriROPNotXOrPen;

                    //Flash the input polygon geometry.
                    display.SetSymbol(symbol);
                    display.DrawPolygon(geometry);
                    System.Threading.Thread.Sleep(delay);
                    display.DrawPolygon(geometry);
                    break;
                }

            case esriGeometryType.esriGeometryPolyline:
                {
                    //Set the flash geometry's symbol.
                    ISimpleLineSymbol simpleLineSymbol = new SimpleLineSymbolClass();
                    simpleLineSymbol.Width = 4;
                    simpleLineSymbol.Color = color;
                    ISymbol symbol = simpleLineSymbol as ISymbol; // Dynamic Cast
                    symbol.ROP2 = esriRasterOpCode.esriROPNotXOrPen;

                    //Flash the input polyline geometry.
                    display.SetSymbol(symbol);
                    display.DrawPolyline(geometry);
                    System.Threading.Thread.Sleep(delay);
                    display.DrawPolyline(geometry);
                    break;
                }

            case esriGeometryType.esriGeometryPoint:
                {
                    //Set the flash geometry's symbol.
                    ISimpleMarkerSymbol simpleMarkerSymbol = new SimpleMarkerSymbolClass();
                    simpleMarkerSymbol.Style = esriSimpleMarkerStyle.esriSMSCircle;
                    simpleMarkerSymbol.Size = 12;
                    simpleMarkerSymbol.Color = color;
                    ISymbol symbol = simpleMarkerSymbol as ISymbol; // Dynamic Cast
                    symbol.ROP2 = esriRasterOpCode.esriROPNotXOrPen;

                    //Flash the input point geometry.
                    display.SetSymbol(symbol);
                    display.DrawPoint(geometry);
                    System.Threading.Thread.Sleep(delay);
                    display.DrawPoint(geometry);
                    break;
                }

            case esriGeometryType.esriGeometryMultipoint:
                {
                    //Set the flash geometry's symbol.
                    ISimpleMarkerSymbol simpleMarkerSymbol = new SimpleMarkerSymbolClass();
                    simpleMarkerSymbol.Style = esriSimpleMarkerStyle.esriSMSCircle;
                    simpleMarkerSymbol.Size = 12;
                    simpleMarkerSymbol.Color = color;
                    ISymbol symbol = simpleMarkerSymbol as ISymbol; // Dynamic Cast
                    symbol.ROP2 = esriRasterOpCode.esriROPNotXOrPen;

                    //Flash the input multipoint geometry.
                    display.SetSymbol(symbol);
                    display.DrawMultipoint(geometry);
                    System.Threading.Thread.Sleep(delay);
                    display.DrawMultipoint(geometry);
                    break;
                }
        }
        display.FinishDrawing();
    }

However, when I use these code like this:

ZoomToGeometry(m_interPointList[e.RowIndex] as IGeometry, m_activeView);
        FlashGeometry(m_interPointList[e.RowIndex] as IGeometry, 
            CommonFunctions.GetColorByRGBValue(255, 0, 0) as IRgbColor, m_activeView.ScreenDisplay, 100);

the ArcMap will first flash that geometry on the screen, and then zoom to the geometry. This is the wrong order, I want it first zoom to the geometry, then flash...

I've tried many ways, I can't solve this problem. Hope someone can help?

Answer 1

The problem is that activeView.Refresh() just invalidates screen rectangle, but doesn't start redraw immediately. Try to call activeView.ScreenDisplay.UpdateWindow() just after Refresh().

BTW, there is a ESRI.ArcGIS.Controls.HookHelperClass that can be used for zooming and flashing.

Examples: hookActionsZoom, hookActionsFlash.