Problem with ArcGISDynamicMapServiceLayer.visibleLayers in Flex 3.0

[GerardoArmendariz]

After upgrading to ArcGIS for Flex 3.0, I am getting the following error:

1118: Implicit coercion of a value with static type mx.collections:IList to a possibly unrelated type mx.collections:ArrayCollection.

I am getting this because of a change to the visibleLayers type in 3.0:

 public function showLayer(layerInfo:LayerInfo):void             {                 var visibleLayers:ArrayCollection;                 if (layer is ArcGISDynamicMapServiceLayer)                 {                     visibleLayers = ArcGISDynamicMapServiceLayer(layer).visibleLayers;                     visibleLayers.addItem(layerInfo.layerId); // add id                 }

Has anyone found a solution to this?  I could not find any in the forum.

[RobertScheitlin__GISP · Accepted solution]

Rie,

   Sure in the 3.0 API the value of

ArcGISDynamicMapServiceLayer(layer).visibleLayers;

could be null now it does not automatically return the default visibility of the layer as it did in previous version so you need to check if it is null first. If it is null then you need to build an array collection with the layers default visibility like this:

            private function buildVisibleLayers(value:Array):ArrayCollection             {                 var ac:ArrayCollection = new ArrayCollection();                 var li:LayerInfo                 for each( li in value){                     if(li.defaultVisibility)                         ac.addItem(li.layerId);                 }                 return ac;             }

So untimately it would look something like this:

                    if(!ArcGISDynamicMapServiceLayer(layer).visibleLayers){                         visibleLayers = buildVisibleLayers(ArcGISDynamicMapServiceLayer(layer).layerInfos);                     }else{                         visibleLayers = ArcGISDynamicMapServiceLayer(layer).visibleLayers as ArrayCollection;                     }

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[GerardoArmendariz]

Thanks for your help.