topic Re: How to return QueryTask results? in ArcGIS JavaScript Maps SDK Questions

How to return QueryTask results?

Anonymous User — Mon, 13 Feb 2017 18:55:19 GMT

How to return QueryTask results? I read the QueryTask returns a promise and this has to be resolved asynchronous way. I looked at other similar posting and one of them said QueryTask uses Deferred, but I am new to Dojo and I couldn't quite understand how Deferred works. I searched references online as much as I can, but unfortunately, I couldn't find one that displays examples similar to my case. I would appreciate any of your help.

Thank you,

Makiko

Re: How to return QueryTask results?

Drew — Sat, 11 Dec 2021 20:55:02 GMT

Your code looks fine (assuming your query is valid) and your results are in the ' results' object..

Do a console.debug on that and you can see the result.

 queryTask.execute(query, addPointsToMap).then(function(results){
 
 console.debug(results)
 
 }));‍‍‍‍‍

Drew

Re: How to return QueryTask results?

Drew — Sat, 11 Dec 2021 20:55:04 GMT

After looking a little closer i can see you are really asking how to get your buildingAttributes variable out...

So it would be more like this..

 _test:function()
{
     queryTask.execute(query, addPointsToMap).then(lang.hitch(this, this._onQueryComplete));
   
},

_onQueryComplete:function(results)
{
     console.debug(results)
}‍‍‍‍‍‍‍‍‍‍

Re: How to return QueryTask results?

RobertScheitlin__GISP — Sat, 11 Dec 2021 20:55:07 GMT

Line 18 below is where you need to add you console statement.

_getFeatureLayerAttributes: function(){
  // Add Building Footprint layer
  var queryTask = new QueryTask({
    url: "https://services.arcgis.com/.../arcgis/services/...FeatureServer/0"
  });
  var buildingAttributes = [];
  var query = new Query();
  query.where = 'Building_Height > -1';
  query.outFields = ['OBJECTID', 'Building_Height', 'Z_Min', 'Z_Max'];
  
  queryTask.execute(query).then(function(results){
    for(var i = 0; 1 < results.features.length; i++){
      var feature = results.features[i].attributes;
      var attr = {OBJECTID: feature.OBJECTID, Building_Height: feature.Building_Height,
                  Z_Min: feature.Z_Min, Z_Max: feature.Z_Max};
      buildingAttributes.push(attr); // <--- How to return this???
    }
    console.log(buildingAttributes); // <--- Right here is where you need to add it
  });
  //console.log(buildingAttributes) ---> This is not printed
},‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: How to return QueryTask results?

Anonymous User — Mon, 13 Feb 2017 19:28:21 GMT

Hi Andrew,

Thank you so much!! I need to familiar with lang.hitch. Your answer is very useful!!

Thanks!!