engine中如何做关联并查询？

//关联

IWorkspace pWkspace = null; 

pWkspace = repeat.Connect_SDE(); 

IFeatureWorkspace featureWorkspace = (IFeatureWorkspace)pWkspace; 



// Open the participating classes from the workspace. 

IObjectClass originClass = featureWorkspace.OpenFeatureClass(SDE.cities); 

IObjectClass destinationClass = (IObjectClass)featureWorkspace.OpenTable(SDE.attribute); 



// Build a memory relationship class. 

Type memRelClassFactoryType = Type.GetTypeFromProgID( 

esriGeodatabase.MemoryRelationshipClassFactory); 

IMemoryRelationshipClassFactory memRelClassFactory = 

(IMemoryRelationshipClassFactory)Activator.CreateInstance(memRelClassFactoryType) 

; 

IRelationshipClass relationshipClass = memRelClassFactory.Open(ParcelsOwners, 

originClass, OBJECTID, destinationClass, OBJECTID, 

Is Owned By, Owns, esriRelCardinality.esriRelCardinalityOneToOne); 



// Open the RelQueryTable as a feature class. 

Type rqtFactoryType = Type.GetTypeFromProgID(esriGeodatabase.RelQueryTableFactory); 

IRelQueryTableFactory rqtFactory = (IRelQueryTableFactory)Activator.CreateInstance 

(rqtFactoryType); 

ITable relQueryTable = (ITable)rqtFactory.Open(relationshipClass, false, null, null, 

String.Empty, false, false); 



/查询

IQueryFilter qf = new QueryFilterClass(); 

qf.WhereClause = ; 

ICursor cursor = relQueryTable.Search(qf, false); 

int count = 0; 

while (cursor.NextRow()!= null) 

{ 

count++; 

} ​