topic Re: saving a graphics layer in ArcGIS API for Silverlight Questions

saving a graphics layer

MarkBaird — Wed, 02 Feb 2011 16:09:56 GMT

I'm working on an application which uses a graphics layer to generate markup. I'd like to be able to save the markup into a file so it can be reloaded at a later date. Storing the markup in a feature class in a database is not an option.

Does anyone know a way of serializing / deserializing a graphics layer or even individual graphics to save / load from a file?

Re: saving a graphics layer

KevinDeege — Wed, 02 Feb 2011 16:16:23 GMT

You could try using Isolated Storage:

private void SaveGraphics_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                //Save the graphics layer
                GraphicsLayer graphicsLayer = MyMap.Layers["StatesGraphicsLayer"] as GraphicsLayer;
                GraphicCollection pGC = graphicsLayer.Graphics;

                //Isolated Storage -- Write Graphics
                IsolatedStorageFile isf = IsolatedStorageFile.GetUserStoreForApplication();

                using (Stream pStream = isf.OpenFile(_ISFileName, FileMode.Create, FileAccess.Write))
                {
                    StreamWriter pStreamWriter = new StreamWriter(pStream);
                    foreach (Graphic g in pGC)
                    {
                        if (g.Geometry is ESRI.ArcGIS.Client.Geometry.MapPoint)
                        {
                            MapPoint pPoint = (MapPoint)g.Geometry;
                            pStreamWriter.WriteLine("Point, " + pPoint.X.ToString() + ", " + pPoint.Y.ToString());
                        }

                        if (g.Geometry is ESRI.ArcGIS.Client.Geometry.Polyline)
                        {
                            ESRI.ArcGIS.Client.Geometry.Polyline pPolyline = (ESRI.ArcGIS.Client.Geometry.Polyline)g.Geometry;
                            ESRI.ArcGIS.Client.Geometry.PointCollection[] pPC = pPolyline.Paths.ToArray();
                            pStreamWriter.Write("Polyline, ");

                            foreach (MapPoint p in pPC[0])
                            {
                                pStreamWriter.Write(p.X.ToString() + ", " + p.Y.ToString() + ",");
                            }
                            pStreamWriter.WriteLine();
                        }

                        if (g.Geometry is ESRI.ArcGIS.Client.Geometry.Polygon)
                        {

                            ESRI.ArcGIS.Client.Geometry.Polygon pPolygon = (ESRI.ArcGIS.Client.Geometry.Polygon)g.Geometry;
                            ESRI.ArcGIS.Client.Geometry.PointCollection[] pPC = pPolygon.Rings.ToArray();
                            pStreamWriter.Write("Polygon, ");

                            foreach (MapPoint p in pPC[0])
                            {
                                pStreamWriter.Write(p.X.ToString() + ", " + p.Y.ToString() + ",");
                            }
                            pStreamWriter.WriteLine();
                        }
                    }
                    pStreamWriter.Close();
                    pStream.Close();
                }
            }
            catch
            {
                MessageBox.Show("Error", "Error", MessageBoxButton.OK);
            }
        }

Re: saving a graphics layer

MarkBaird — Wed, 02 Feb 2011 17:55:53 GMT

Hi Kevin,

Thanks for the reply. I was kind of hoping that I wouldn't need to dive into the components of the geometry, but your code gives me the technique of doing this so that helps loads. I was hoping I might have missed a geometry.toJson/fromJson method or something similar. I'm probably going to create an XML structure to store this.

Out of interest do you have a sample line of code which takes MapPoints and puts them back into the Ring of a Polygon for example. If not I'll soon work it out 🙂

Thanks

Re: saving a graphics layer

DominiqueBroux — Wed, 02 Feb 2011 19:05:15 GMT

There is an example of GraphicsLayer serialization here : http://forums.arcgis.com/threads/8774-save-layer-to-xml-file but there are some limitations : for example the symbols are not serialized.

Re: saving a graphics layer

MarkBaird — Thu, 03 Feb 2011 13:56:03 GMT

That serialisation example was just the answer!

I've adapted my graphics layer to use the attributes to store the symbology and it works really well. Thanks again!

Re: saving a graphics layer

AdrianMarsden — Fri, 15 Mar 2013 09:39:08 GMT

sorry please ignore - didn't notice forum I was posting in