Does a featureLayer, based on a featureCollection, support query by ObjectID?

StephenLead

It's possible to create a featureLayer on-the-fly using a featureCollection, as described at http://help.arcgis.com/en/webapi/javascript/arcgis/jsapi/#FeatureLayer/FeatureLayerConst2, which also mentions:

• The feature layer generates a unique object id for new features.
• Does not support queries that need to be performed on the server, e.g. queries with a where clause

Does this mean that a featureLayer based on a featureCollection will not support featureLayer.queryFeatures based on query.objectIds as in this example?

 var query = new esri.tasks.Query(); query.objectIds = [features[0].attributes.OBJECTID]; query.outFields = [ "*" ]; // Query for the features with the given object ID featureLayer.queryFeatures(query, function(featureSet) { });

I'm seeing sporadic results, with the query sometimes working and sometimes not working. Unfortunately I don't have an easily reproducible piece of code that I can share.

Thanks for any advice,
Steve

StephenLead

I seem to have answered my own question, which is that a featureLayer based on a featureCollection does support query by objectID.

Read on if you're interested in verifying this.....

Sample code here - it's pretty rough, with no error checking, but here's how to demonstrate that it works:

- an empty featureLayer is created when the map loads
- hit the Find button at the top left of the map
- any lakes with a name starting with "LAKE CR%" will be added to the feature layer
- these are shown in pink on the map, and their ObjectIDs are written to the firebug console
- make a note of one of the ObjectIds and enter it into the text box at the top left
- hit the Query ObjectId button and see the results in the console

If you use the Find button again, it deletes the existing features and re-adds new features, which have incremented ObjectIds.

In my other code, I'm finding that in this case the queryFeatures function is not finding the new features (eg where objectId = 14). Since it's working correctly here, my "sporadic" problems must lie elsewhere in my code.

Cheers,
Steve

Update: in my other code, I was only passing a single ObjectID object, rather than an array of [ObjectIds] as required. Strangely, this worked some of the time.