topic Re: Query WMS Layer in ArcGIS API for Silverlight Questions

Query WMS Layer

MarieChan-Gove — Thu, 30 Jun 2011 17:32:58 GMT

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.

Re: Query WMS Layer

dotMorten_esri — Sat, 02 Jul 2011 00:10:19 GMT

The WMS Layer in the API does not provide support for the GetFeature request in WMS Layers out of the box.

Re: Query WMS Layer

OscarLexell — Sun, 12 Dec 2021 01:01:14 GMT

I've a similar problem.

Following the example for spatial query and replacing the commented link with a new link

//QueryTask queryTask = new QueryTask("http://sampleserver1.arcgisonline.com/ArcGIS/rest/services/Demographics/ESRI_Census_USA/MapServer/5");
QueryTask queryTask = new QueryTask("http://maps.helcom.fi/ArcGIS/rest/services/DataDeliveryNoSublayers/MapServer/132");

And

 //query.OutFields.AddRange(new string[] { "STATE_NAME", "SUB_REGION", "STATE_FIPS", "STATE_ABBR", "POP2000", "POP2007" });
                query.OutFields.AddRange(new string[] { "ET_FID", "ID", "COUNTRY", "AIRCRAFT", "SPEED_KN", "RS_EQUIP" });

The wms layer is defined as

<esri:WmsLayer ID="- Aircrafts" Url="http://maps.helcom.fi/ArcGIS/services/DataDelivery/MapServer/WMSServer?" 
                            ProxyUrl="http://serverapps.esri.com/SilverlightDemos/ProxyPage/proxy.ashx"  Version="1.3.0" Layers="179"
                               SkipGetCapabilities="True" Initialized="WmsLayer_Initialized" Visible="True" InitializationFailed="layer_InitializationFailed"/>

the WMS layer is inside two group layers

Trying this i got this error
[ATTACH=CONFIG]13484[/ATTACH]

the crossdomain.xml file I think is in the correct location.

Maybe the problem is more layers being selected and Query tasks trying to query the wrong layer?

Any good sugestion on how to get on?

Re: Query WMS Layer

DominiqueBroux — Mon, 16 Apr 2012 05:49:57 GMT

As you need a proxy for your map service, likely you need one for the query task as well.
Did you put a proxy for the query task?

Else you can look to the query sent to the server by using an HTTP sniffer such as fiddler. This might give a clue.

Re: Query WMS Layer

OscarLexell — Wed, 18 Apr 2012 09:41:14 GMT

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.

Re: Query WMS Layer

DominiqueBroux — Thu, 19 Apr 2012 08:14:46 GMT

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.

View and Query WMS Layer Dynamically From ArcGIS Silverlight API

İsmailZAMBAKCI — Sat, 14 Dec 2013 19:21:07 GMT

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 🙂