Hiding/showing graphics using .hide and .show issue

Question

Panning seems to be fairly choppy when there are numerous objects on the graphics layer (in my case, building footprints). I decided that a workaround would be to hide the graphics layer while panning, and then restore visibility.

The code, I think, should be fairly simple, but the following script does not work. I've tried setting the visibility, doing a redraw/refresh on the lyrBuildings layer. Nothing seems to bring those objects back except zooming in or out. What am I missing?

dojo.connect(map, "onPanStart", function(){
    lyrBuildings.hide();
});

dojo.connect(map, "onPanEnd", function(){
    lyrBuildings.show();
});

derekswingley1 · Answer

You can set displayOnPan on a per layer basis:  it's an option to the constructor for graphics layer (as well as feature layer).

StephenLead · Answer

Just a tip, when you paste code in the forums, use the # option at the top right - this prevents the forum from stripping your formatting.

I can't get to your buildings layer so it's hard to test, but your code looks right to me. Have you tried putting a debug breakpoint on lines 40 and 44 to see whether the show/hide code is firing?

One question is why you need to run a query then add the graphics to the layer - why not just define the buildings layer as a standard feature layer? This may handle the number of graphics better.

You could also try putting the query inside the map's onLoad event:
dojo.connect(map, "onLoad", function() {
    var queryTask = new esri.tasks.QueryTask("https://maps.admin.umass.edu/arcgis/rest/services/umaFacilities/umaFacilitiesOperationalLayers/FeatureServer/2" );
    var query = new esri.tasks.Query();
    query.where = "1=1";
    query.returnGeometry = true;
    query.outFields = ["LONGNAME"];
    queryTask.execute(query, addPointsToMap);
});

Sorry I can't help more,
Steve

MatthewGoulet1 · Answer

Steve, Thanks for your suggestion. Unfortunately, it applies only to the map object, not its constituent layers. Here is my code; I apologize if it is very messy! Untitled 1