Number of graphics in current view

Question

I'm looking to get the number of graphics being shown by a FeatureLayer in a map. I'm currently using the feature layer's numGraphics property which works as I would expect, until I start zooming in. I have a handler for the layer's updateEnd event which is where I check for the numGraphics value. All works as expected, but once I zoom in to a certain point the value never changes. Say I start with 500 points showing, then zoom in to a point where only 2 points are showing, the numGraphics value still shows 500. Is there another property I should be looking at? Or, should I be checking this from some other event? It looks like numGraphics does what I want, but at some point it appears as though the flex app is caching and not re-reading the map service. I'm stumped on this one. I have the layer set as a FeatureLayer in onDemand mode. Any help is greatly appreciated.

KeithWeber1 · Answer

I am trying to get the same functionality. I have a popup window that contains the ESRI attribute table and want to have a label underneath the attribute table that displays the number of records in the table. When I set the onDemandCacheSize property to zero, I do notice that the value of numGraphics updates, but it is not consistent with the number of features on the map or in the attribute table. Is there any other way to get this value? How is the attribute table able to get the features that are in view?

DerrickMartin · Answer

Thanks Bjorn! Setting this to cache size 0 makes it behave exactly how I wanted. I know this is probably not the best way to go about this but for the particular app, it's more of a reporting tool so it's working perfect for us. Thanks again!

BjornSvensson · Answer

When using the on demand mode, you also need to be aware of the onDemandCacheSize property.
"When the query mode is MODE_ON_DEMAND and there are more than this number of features loaded, features that are not selected and are not in the current extent are removed in FIFO order (first in, first out). If this value is 0, features in the current extent are also removed.
The default value is 1000 features."
http://help.arcgis.com/en/webapi/flex/apiref/com/esri/ags/layers/FeatureLayer.html#onDemandCacheSize