/// <summary>
/// Handles the collection restriction before evaluating the result
/// </summary>
/// <param name="collection">A collection to further restrict</param>
/// <returns>A further restricted collection</returns>
private FeatureCollection RestrictedCollection(FeatureCollection collection)
{
if (collection != null && LiteClientSettingsViewModel.Instance.QueriesUseRestrictionAreas)
{
// Check whether we can restrict the collection
var message = new LiteRestrictFeatureCollectionRequestMessage(this, collection);
// Ask other viewModels via the messenger
Messenger.Send(message);
// Get the restricted collection from the message
collection = message.RestrictedCollection;
}
return(collection);
}
/// <summary>
/// Handle the restriction of a feature collection
/// </summary>
private void HandleRestrictFeatureCollection(LiteRestrictFeatureCollectionRequestMessage restrictionRequest)
{
// The sample behavior is to restrict the collection based on the MapLayerAreas that have been
// set up for this user (its groups). In case there are restriction areas set up, the extra restriction
// will be set on geometry fields that are set up in the restriction data collection
// Restrict the Town collection
var restrictionGeometry = LiteClientSettingsViewModel.Instance.RestrictionGeometry;
var sourceCollection = restrictionRequest.RestrictedCollection;
if (restrictionGeometry != null && sourceCollection != null)
{
var table = sourceCollection.TableDescriptor;
if (table != null)
{
string fieldName;
if (_tableFieldNamesToRestrictByArea.TryGetValue(table.Name, out fieldName))
{
// Do explicit restriction via the table/field combination
var coverageField = table.FieldDescriptors[fieldName];
if (coverageField != null && coverageField.IsGeometry)
{
var extraRestriction = glf.Spatial.Interacts(glf.Data.Field(coverageField), glf.Constant(restrictionGeometry));
restrictionRequest.RestrictedCollection = sourceCollection.Where(extraRestriction);
}
}
else if (IncludeDefaultRestrictions)
{
// Try to restrict by investigating the geometry fields of the collection
// If there is a GeoGraphic field, let's try and restrict the lot according to our areas
if (table.FieldDescriptors.FirstOrDefault(f =>
{
var geometryField = f as FeatureGeometryFieldDescriptor;
return(geometryField != null && geometryField.IsSelectableGeometry && geometryField.IsGeographic);
}) != null)
{
var extraRestriction = glf.Function(SpatialEye.Framework.Features.Expressions.GeoLinqExpressionType.SpatialAnyInteracts, glf.Data.Table(table), glf.Constant(restrictionGeometry));
restrictionRequest.RestrictedCollection = sourceCollection.Where(extraRestriction);
}
}
}
}
}