[mapguide-users] Selection Issue (FeatureReader only grabbing 20 items)

[Ronnie Louie]

Your code is calling MgSelection::GenerateFilters() which has limitation in that it only generates a filter for the first 20 items.  This limitation was introduced by http://trac.osgeo.org/mapguide/changeset/3053.

A follow up submission to address this added a temporary, undocumented API, GenerateFilters to resolve the limitation.  See http://trac.osgeo.org/mapguide/ticket/501.

To workaround the issue until a fix for GenerateFilter is available, you can use the undocumented GenerateFilters to create the filters, and then perform your selection based on each of the filters.  Iterate through the features in each feature reader to get all your features.  Please be aware this is offered only as a workaround until GenerateFilter is fixed.

Have a look at http://svn.osgeo.org/mapguide/branches/2.0.x/MgDev/Web/src/mapviewerphp/buffer.php for a sample of how to use the GenerateFilters method to setup the query for selection.


Ronnie


-----Original Message-----
From: nclayton [mailto:nclayton at gmail.com]
Sent: Monday, July 21, 2008 9:25 AM
To: mapguide-users at lists.osgeo.org
Subject: [mapguide-users] Selection Issue (FeatureReader only grabbing 20 items)


Hi all,
This has just recently become a problem. I am passing the selection xml to a
page to display parcel owner data. For an example, I select 256 parcels on
the map. The selection xml comes over fine, with all 256 parcels listed.
When I use a featureReader to get the parcel numbers from the features, It
only get the first 20.

Is this a setting I may have altered unintentionally, or could there be more
to it?

Here is the code that I am using to pull the information out from the
selection xml:
========================================================================
function GetObjKeys($sessId,$mapName,$sel){
  $obj_keys = '';
    if($sel != ''){
      InitializeWebTier();
      $userInfo = new MgUserInformation($sessId);
      $siteConnection = new MgSiteConnection();
      $siteConnection->Open($userInfo);
      $resourceService =
$siteConnection->CreateService(MgServiceType::ResourceService);
      $featureService =
$siteConnection->CreateService(MgServiceType::FeatureService);
      $map = new MgMap($siteConnection);
      $map->Open($resourceService,$mapName);
      $selection = new MgSelection($map,$sel);
      if($selection != ''){
        $layers = $selection->GetLayers();
        if(!$layers){ $layers = $map->GetLayers(); }
      }else{ $layers = 0; }
      $layer = null;
      if($layers){
      for($i = 0; $i < $layers->GetCount(); $i++){
        if($layers->GetItem($i)->GetName() == "parcels"){ $layer =
$layers->GetItem($i); }
      }
      $queryOptions = new MgFeatureQueryOptions();
      if($layer){
        $layerClassName = $layer->GetFeatureClassName();
        if($sel != ''){ $selString =
$selection->GenerateFilter($layer,$layerClassName); }
        $layerFeatureId = $layer->GetFeatureSourceId();
        $layerFeatureResource = new MgResourceIdentifier($layerFeatureId);
        $layerId = $layer->GetObjectId();
        $queryOptions->SetFilter($selString);
        $featureReader =
$featureService->SelectFeatures($layerFeatureResource,$layerClassName,$queryOptions);
        $selTmp = '';
        for($pdx=0; $pdx<$featureReader->GetPropertyCount(); $pdx++){
          $pnm = $featureReader->GetPropertyName($pdx);
          if($pnm == 'PARCEL_ID_'){ break; }
          if($pnm == 'PARCELID'){ break; }
          if($pnm == 'Key'){ break; }
          $pnm = "";
        }
        if($pnm != ""){
          while($featureReader->ReadNext()){
            $stg = $featureReader->GetString($pnm);
            if($stg != ""){     $obj_keys .= "'" . $stg . "'"; }
          }
        }
        $obj_keys = str_replace("''","','",$obj_keys);
      }
    }
    return $obj_keys;
  }else{ return ''; }
}
--
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