topic FeatureLayer with Selection Mode and QueryTask. in ArcGIS API for Silverlight Questions

FeatureLayer with Selection Mode and QueryTask.

SanajyJadhav — Thu, 09 Feb 2012 02:18:52 GMT

Hello,

I would not say I fully get the concept of FeatureLayer in Selection mode.It seems like showing showing only the selected features from the feature layer.Please correct me if I am wrong.

If it is the case then, can we say that it is same as executing the query on the layer in the map service and hi-lighting its results.

Then could it be summarized that rendering the FeatureLayer in selection mode is equivalent to executing query on the map service layer and showing the result on the map.I would appreciate if anybody could help me get this concept. That means I instead of firing the query, I can just add featurelayer in selection mode.

Thanks.

Re: FeatureLayer with Selection Mode and QueryTask.

RuiShen — Mon, 05 Mar 2012 18:47:48 GMT

Hi Sanjay,
I think you are right about this. If you see the web request sent to the server when using the selection mode, you will see it is actually sending a spatial query.

Rui

Re: FeatureLayer with Selection Mode and QueryTask.

JenniferNery — Wed, 14 Mar 2012 20:09:29 GMT

The following concept page might help: http://help.arcgis.com/en/webapi/silverlight/help/index.html#//016600000015000000

Selection only�??Does not initially request any features. Features are added only when a selection is made. Selection only mode is useful when you cannot or do not want to bring all features into the client, but you want to highlight one or more features for a certain reason. In most cases, this mode is used in conjunction with a dynamic map service layer to display the location of selected features.

In the following SDK sample: http://help.arcgis.com/en/webapi/silverlight/samples/start.htm#FeatureLayerSelection, ArcGISDynamicMapServiceLayer shows an image of where the features are. Using selection tools, we run a query against the feature service and bring them to client FeatureLayer. They only get added to the layer upon selection. Thus, making it look like you are highlighting from ArcGISDynamicMapServiceLayer. The FeatureLayer in this sample use YellowRenderer to differentiate features that are on the layer from features that only exist on server.