topic Re: Trouble getting minimum value from FeatureTable in ArcGIS AppStudio Questions

Trouble getting minimum value from FeatureTable

KeithLarson1 — Tue, 18 Dec 2018 16:45:30 GMT

Hello all,

I am trying to get the minimum value in a table in a FeatureServer. I have tried both the queryStatistics method and using a NetworkRequest object with outStatistics set.

For the queryStatistics problem, I am creating a StatisticsQueryParametes object with a StatisticDefinition specifying the field that I want and that the statisticType should be Enums.StatisticTypeMinimum. I connect a function to the queryStatisticsStatusChanged signal and I see when it is chaned to in progress. However, after a bit of time, I get the error: QObject::connect: Cannot queue arguments of type 'std::shared_ptr<QRTImpl::Stati

sticsQueryResultImpl>' (Make sure 'std::shared_ptr<QRTImpl::StatisticsQueryResultImpl>' is registered using qRegisterMetaType().).

When I tried using a NetworkRequest object, I send the message: {f: "json", outStatistics: [{"statisticType":"min","onStatisticField":"myId", "outStatisticFieldName":"MinID"}]}. The response object gives me the error code 400. I know statistics querying is enabled on this table, because if I go to the query page in my web browser I can put in the same json that I'm setting to outStatistics and I get the result with no problem.

If anyone knows what I'm doing wrong, the help would be greatly appreciated.

Thanks,

Keith

Re: Trouble getting minimum value from FeatureTable

ErwinSoekianto — Tue, 18 Dec 2018 17:25:14 GMT

Keith,

That is weird, technically you should be getting the same result when making the REST request and NetworkRequest.

Can you show us your NetworkRequest component code? There is a possibility that you may be missing some parameters when sending the request that's causing it to return error 400 instead.

Thank you,

Erwin.

Re: Trouble getting minimum value from FeatureTable

KeithLarson1 — Tue, 18 Dec 2018 17:36:47 GMT

This is my NetworkRequest object where I'm just printing out the response:

NetworkRequest {

   id: getMinID

   url: featureServiceUrl

   responseType: "json"

   method: "POST"

   onReadyStateChanged: {

       if (readyState === NetworkRequest.DONE) {

          console.log("Response: " + JSON.stringify(response));

And, here is the request I send:

getMinID.send({f: "json", outStatistics: [{"statisticType":"min","onStatisticField":"myId", "outStatisticFieldName":"MinID"}]});

Re: Trouble getting minimum value from FeatureTable

ErwinSoekianto — Tue, 18 Dec 2018 18:13:12 GMT

Did you make sure that the "featureServiceUrl" has the layer id and query operation?

like this: https://<featureServiceURL>/FeatureServer/0/query

Re: Trouble getting minimum value from FeatureTable

KeithLarson1 — Tue, 18 Dec 2018 18:20:32 GMT

I printed the url and it had the form http://<featureServiceURL>/FeatureServer/2/query which is the correct table as well. I get the response: {"error":{"code":400,"details":["Unable to perform query operation."],"message":"Unable to complete operation."}}