Web API Reference | MapGuide Open Source

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AddComputedProperty
AddFeatureProperty
MgFeatureQueryOptions
RemoveComputedProperty
RemoveFeatureProperty
SetBinaryOperator
SetFilter
SetOrderingFilter
SetSpatialFilter
INT32 MgFeatureQueryOptions::AddComputedProperty | ( | CREFSTRING | aliasName,
|  | CREFSTRING | expression |
| ) |  |  |
Define an alias for a computed property and an expression for what is to be computed. In this SQL example, "select min(aDouble + aSingle) as minF, min(anInt16 + anInt16) as minI from featclass;", minF and minI are computed properties. Call this method for each computed property that you add. .NET Syntax
`int AddComputedProperty(string aliasName, string expression);`
Java Syntax
`int AddComputedProperty(String aliasName, String expression);`
PHP Syntax
`int AddComputedProperty(string aliasName, string expression);`
  Parameters:
  | aliasName | (String/string) The name of the computed property.
  | expression | (String/string) The expression to be associated with the name of the computed property.
Returns: Returns the total number of properties added. Example (PHP)
     <?php
     $queryOptions->AddComputedProperty("minF", "aDouble + aSingle");
     $queryOptions->AddComputedProperty("minI", "anInt64 + anInt16");
     $featureService->SelectFeatures($featureSrcResourceId, $featClassName, $queryOptions);
     $featureService->SelectFeatures($featureSrcResourceId, $featClassName, $queryOptions);
     ?>
     sqlplus> select min(aDouble + aSingle) as minF, min(anInt16 + anInt16) as minI from featclass;
Example (C#)
     using OSGeo.MapGuide;
     private MgFeatureQueryOptions queryOptions;
     private MgFeatureService featureService;
     private String className = "SdfFeatureClass";
     // the SDF file identified by this MgResourceIdentifier exists in the repository
     private MgResourceIdentifier resourceId;
     private MgFeatureReader featureReader;

     resourceId = new MgResourceIdentifier("Library://PlatformApiDocTests/SdfFeatureClass.FeatureSource");
     queryOptions = new MgFeatureQueryOptions();
     queryOptions.AddFeatureProperty("FeatId");
     queryOptions.AddFeatureProperty("aDouble");
     queryOptions.AddComputedProperty("ceilADouble", "Ceil(aDouble)");
     featureReader = featureService.SelectFeatures(resourceId, className, queryOptions);
  Exceptions:
  | MgInvalidArgumentException | if aliasName or expression is empty

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