Odd FeatureLayer Implementation Behavior

Question

I have a need to implement the FeatureLayer class so that i can add my own DependencyProperties, events, etc. I've finally been able to get this to work, but i've noticed some odd behavior. If you:

1. Implement the FeatureLayer class as "MyFeatureLayer" (do nothing else in the class)
   2. Add your "MyFeatureLayer" class to the map as you would a regular FeatureLayer (make all the required settings so that data should load)
   3. Notice that when you load the app the FeatureLayer never completely loads

Somehow i stumbled upon the workaround that if you set the map extent explicitly on the map itself rather than letting it pick up from the first layer that loads, everything seems to work fine.

So, am i try to do something that's not really supported, or is this a bug? I haven't upgraded to the 2.0 RC as we haven't yet upgraded our ArcGIS Server to the 10.0 release version. (currently using beta versions of both)

DonnieHolmes · Answer

Thanks Dominique. Is this behavior by design? I'm just curious as to why the map would ignore feature layers for its extent and spatial reference info.

DominiqueBroux · Answer

You are right the map extent is not initialized from the feature layer.
 
You can initialize the map extent in the featurelayer initialized event:
  
private void FeatureLayer_Initialized(object sender, System.EventArgs e)
{
FeatureLayer featureLayer = sender as FeatureLayer;
MyMap.Extent = featureLayer.LayerInfo.Extent;
}

DonnieHolmes · Answer

I finally figured out what is wrong, and it doesn't appear related to implementing the FeatureLayer class. It seems that if there is only a FeatureLayer in the map, then it won't pay any attention to it unless you explicitly set the map extent. Using data from the ESRI sample services: This loads as expected: Nothing loads for this scenario: However, this does work (which does nothing more than set the map to the extent and spatial ref of the feature layer): This seems like a bug to me.