Developer's Guide - MapGuide Open Source - OSGeo

4 Initialize the MgSelection object with the list of features passed to the
page.
5 Retrieve selected layers from the MgSelection object.
6 For each layer, retrieve selected feature classes. There will normally be
one feature class for the layer, so you can use the
MgSelection::GetClass() method instead of the
MgSelection::GetClasses() method.
7 Call MgSelection::GenerateFilter() to create a selection filter that
contains the selected features in the class.
8 Call MgFeatureService::SelectFeatures() to create an MgFeatureReader
object for the selected features.
9 Process the MgFeatureReader object, retrieving each selected feature.
Example: Listing Selected Parcels (AJAX Viewer)
To run the following example, view a map created with the sample data. Using
one of the selection tools, select one or more parcels.
NOTE The sample code below is not complete. You must perform standard
initialization steps and exception trapping.
The example creates a Resource Service connection to open the map and a
Feature Service connection to read the feature information. In addition, you
will require an MgFeatureQueryOptions object for creating the list of features.
The MgSelection object contains selection information for a given map. It
can either contain the current selection or a selection created from XML data.
For this example, create the object with the current map selection.
Get the list of layers and iterate through them. When the $layers collection
is empty, there are no features selected.
Working With the Active Selection | 47