topic Re: How can I clone a graphic object? in ArcGIS API for Silverlight Questions

How can I clone a graphic object?

weiliang — Sun, 15 May 2011 15:58:56 GMT

Hi,

I want to clone a graphic object but find that it doesn't implement the ICloneable interface. Then how can I fulfill this graphic clone purpose? Will ESRI plans to make the graphic cloneable in next release?

Thanks,

Wei

Re: How can I clone a graphic object?

DominiqueBroux — Mon, 16 May 2011 06:47:22 GMT

I am not aware to any plan to implement the ICloneable interface.

For a solution, look at this thread : http://forums.arcgis.com/threads/30252-How-to-create-a-new-graphic-similar-to-a-graphic-in-some-featureLayer

Re: How can I clone a graphic object?

weiliang — Mon, 16 May 2011 18:08:00 GMT

Many thanks, Dominique. But I thought geometry is reference type, why it is not and don't need to be deep cloned? I'm a little bit confused.

   For example the code below, why after the last line is been executed, the gra.Geometry is not null:
            MapPoint mapPoint = new MapPoint(2.4, 42.6);
            Graphic gra = new Graphic();
            gra.Geometry = mapPoint;
            mapPoint = null;

Thank again,

Wei

Re: How can I clone a graphic object?

DominiqueBroux — Tue, 17 May 2011 06:57:46 GMT

Many thanks, Dominique. But I thought geometry is reference type, why it is not and don't need to be deep cloned?

Hi Wei,

You may have to clone the geometry depending on what you are doing with your graphics. If you want to be able to move a graphic without moving its clone, you have to deep clone the geometry.
Luckily the geometry class supports a 'Clone' method. So easy to do:)

For example the code below, why after the last line is been executed, the gra.Geometry is not null:
MapPoint mapPoint = new MapPoint(2.4, 42.6);
Graphic gra = new Graphic();
gra.Geometry = mapPoint;
mapPoint = null;

'mapPoint = null;' changes the object the variable is referencing to but doesn't change the object itself. So gra.geometry is not impacted.

However, if you set 'mapPoint.X=0;mapPoint.Y=0;', you would change the geometry of your graphic since mapPoint and gra.Geometry are referencing the same object.

Re: How can I clone a graphic object?

weiliang — Tue, 17 May 2011 18:50:21 GMT

Thanks, Dominique. It's good to know that set the variable to null isn't really clear the heap object.

Wei