Query WMS Layer

Question

Hello
I am a newbie at Siverlight and WMS.  I followed the Silverlight Interactive SDK and able to load WmsLayer in XAML successfully; thus, I can see the features on the map.  But, I am not able to go further, i.e. query info in the WmsLayer.  I tried QueryTask but it gave me errors.

I am looking for example C# code and/or documentation of how to query WmsLayer.

Please help.

İsmailZAMBAKCI · Answer

Hi, You can write a proxy page has that capabilites;
-Gets arcgis request from any arcgis client api (flex-silverlight-javascript-...).
-Prepares the wms request for send to geoserver or other ogc servers.
-Gets response of the ogc getcapabilities,describefeaturetype and the other request types responses.
-Convert response xml or xsd reponses that returns from wms, to ArcGIS json format.

And you can use an ogc service as below,
layer = new ArcGISDynamicMapServiceLayer() 
{ ID ="GeoServer WMS", 
   Url = "http://demo.opengeo.org/geoserver/osm/wms", 
   ProxyURL = "Your proxy page " 
};

I have written that proxy and Im looking for editing capabilities for convert to use wfs-t services.
I think, It will not be easy 🙂

DominiqueBroux · Answer

The proxy was of no use.

Strange. If you are able to display the layer using a proxy, you should be able to query it by using the same proxy.
I've found the crossdomain.xml is not in the root.
http://maps.helcom.fi/website/crossdomain.xml
How to tell Silverlight to look for the crossdomain.xml here instead?

crossdomain or cliantaccesspolicy files must be in the root of the website. AFAIK, there is no way to change this behavior.Still interesting in knowing if it is possible to read the crossdomain.xml file without using fiddler AutoResponder.

Proxy should be the solution.

OscarLexell · Answer

Thank you.

The proxy was of no use. bur fiddler give a clue.
I've found the crossdomain.xml is not in the root.
http://maps.helcom.fi/website/crossdomain.xml
How to tell Silverlight to look for the crossdomain.xml here instead?
I'm not sure if this will help, but it is the only crossdomain or clientaccesspolicy I can find.

Edit, by using Fiddler AutoResponder I can trick the application to read a local clientaccesspolicy.xml or the crossdomain linked above. Now the query works and I will start to figure out how to query several layers.

Still interesting in knowing if it is possible to read the crossdomain.xml file without using fiddler AutoResponder.